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51. MARÉE DANS L'ESTUAIRE DE LA GIRONDE

Author: Jan, Gwenaële, Lyard, Florent, Allain, Damien, Tchilibou, Michel, Penney, Jarred, Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS), Shom, Ifremer, EuroiGOOS AISBL, Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: numerical modelling of tidal wave distortion, water level measurement, [SDE]Environmental Sciences, river dynamics and environmental key points
Abstract: International audience; The study investigates the dynamics of the Gironde estuary in order to improve the tidal wave deformation modelling in a constrained environment. The need has been highlighted by statistics over high and low tides and surges, upstream of Fort Medoc (Figure 1) (SHOM & Grand Port Maritime de Bordeaux project, 2013). A numerical model has been confi gured and supplemented by a multi-sensor in situ measurement campaign. The challenge is to separate the part of the physics explicitly solved by the model from what cannot be solved and must consequently be parameterized with physical resolution ranging, here, from 10 m to 1 km. The results show the improvement in reproducing the deformation of tidal wave, disturbed by river fl ow and atmospheric stress. From the analysis at tide gauge stations, the mean standard deviation of the amplitude difference between model and observations is now close to 0.03 m, which is an improvement of the score previously obtained (0.10 up to 1.0 m, depending on river fl ow and atmospheric conditions). Navigation safety along the Gironde River and the risk of fl ooding camp the motivations of the present study. The expectation of infrastructure for navigation in the estuary is acute.
Published: 2021

52. Seasonal and Interannual Variability of the CO2 System in the Eastern Mediterranean Sea: A Case Study in the North Western Levantine Basin

Author: Cathy Wimart-Rousseau, Thibaut Wagener, Marta Álvarez, Thierry Moutin, Marine Fourrier, Laurent Coppola, Laure Niclas-Chirurgien, Patrick Raimbault, Fabrizio D’Ortenzio, Xavier Durrieu de Madron, Vincent Taillandier, Franck Dumas, Pascal Conan, Mireille Pujo-Pay, Dominique Lefèvre, Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Instituto Espagňol de Oceanografia (IEO), Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre de Formation et de Recherche sur les Environnements Méditérranéens (CEFREM), Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Laboratoire d'Océanographie Microbienne (LOMIC), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Université de Perpignan Via Domitia (UPVD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN), Centre de recherches interdisciplinaires et transculturelles - UFC (EA 3224) (CRIT), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), and EMSO ERIC, Rome, Italy
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Science, Ocean Engineering, Aquatic Science, QH1-199.5, Oceanography, 01 natural sciences, chemistry.chemical_compound, acidification, Mediterranean sea, Water column, CO 2 fluxes, Total inorganic carbon, Mediterranean Sea, Levantine Sea, carbonate system, 14. Life underwater, Argo, 0105 earth and related environmental sciences, Water Science and Technology, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Global and Planetary Change, 010604 marine biology & hydrobiology, General. Including nature conservation, geographical distribution, Ocean acidification, Annual cycle, CO2 fluxes, chemistry, 13. Climate action, [SDE]Environmental Sciences, Carbonate, Seawater, inorganic carbon
Abstract: The seasonal variability of the carbonate system in the eastern Mediterranean Sea (EMed) was investigated based on discrete total alkalinity (AT), total dissolved inorganic carbon (CT), and pH measurements collected during three cruises around Crete between June 2018 and March 2019. This study presents a detailed description of this new carbonate chemistry dataset in the eastern Mediterranean Sea. We show that the North Western Levantine Basin (NWLB) is unique in terms of range of AT variation vs. CT variation in the upper water column over an annual cycle. The reasons for this singularity of the NWLB can be explained by the interplay between strong evaporation and the concomitant consumption of CT by autotrophic processes. The high range of AT variations, combined to temperature changes, has a strong impact on the variability of the seawater pCO2 (pCO2SW). Based on Argo float data, an entire annual cycle for pCO2SW in the NWLB has been reconstructed in order to estimate the temporal sequence of the potential “source” and “sink” of atmospheric CO2. By combining this dataset with previous observations in the NWLB, this study shows a significant ocean acidification and a decrease in the oceanic surface pHT25 of −0.0024 ± 0.0004 pHT25 units.a–1. The changes in the carbonate system are driven by the increase of atmospheric CO2 but also by unexplained temporal changes in the surface AT content. If we consider that the EMed will, in the future, encounter longer, more intense and warmer summer seasons, this study proposes some perspectives on the carbonate system functioning of the “future” EMed.
Published: 2021
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53. LANS-α turbulence modeling for coastal sea: An application to Alderney Race

Author: Freddy Adong, Franck Dumas, Anne-Claire Bennis, Martial Boutet, Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Service Hydrographique et Océanographique de la Marine (SHOM), and Ministère de la Défense
Subjects: Inertial frame of reference, Physics and Astronomy (miscellaneous), Flow (psychology), 010103 numerical & computational mathematics, Oceanography, 01 natural sciences, Physics::Fluid Dynamics, Barotropic fluid, Numerical modeling, Range (statistics), Marine turbulence, 0101 mathematics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Numerical Analysis, Turbulence, Applied Mathematics, Large eddy simulation, Turbulence modeling, Mechanics, Computer Science Applications, 010101 applied mathematics, Computational Mathematics, Modeling and Simulation, Dissipative system, LANS-alpha models, Geology
Abstract: The Lagrangian-Averaged Navier-Stokes-α (LANS-α) turbulence model was implemented for the first time in a coastal hydrodynamic model. We present in this paper the details of the implementation, as well as the difficulties encountered. To overcome the difficulties, a convolution filter was used instead of the Helmoltz operator, and incompressibility was imposed in both rough and smooth velocities. The results of the second numerical implementation were tested against the results of simulations without LANS-α for a realistic application showing the tidal dynamic in Alderney Race, Normandy, France, which has the strongest currents in western Europe. The behavior of LANS-α is consistent with the conclusions of former studies, which supports our results. The findings are: i) LANS-α re-energizes the flow recovering higher-resolution turbulence statistics in lower-resolution simulations, leading to 30% savings in computing time, ii) LANS-α produces the two kinds of inertial range for barotropic turbulence, with turbulent energy decays in k − 5 / 3 and in k − 3 (k being the wave number) and iii) LANS-α strongly characterizes the turbulence induced by deformation. In the future, these results need to be compared to measurements and to other turbulence modeling approaches, including dissipative LES or DNS, to evaluate their relevance for the community.
Published: 2021
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54. BGC‐Argo Floats Observe Nitrate Injection and Spring Phytoplankton Increase in the Surface Layer of Levantine Sea (Eastern Mediterranean)

Author: L. Terrats, Marine Fourrier, Alexandra Pavlidou, A. Oviedo, Thibaut Wagener, M. Puyo‐pay, M. Ribera d'Alcalà, Cathy Wimart-Rousseau, Antoine Poteau, Laurent Coppola, Dominique Lefèvre, Alexandra Gogou, Catherine Schmechtig, Pascal Conan, Stella Psarra, Franck Dumas, Hervé Claustre, Louis Marie Prieur, Vincent Taillandier, Fabrizio D'Ortenzio, Pierre-Marie Poulain, Edouard Leymarie, A.P. Karageorgis, X. Durrieu Du Madron, Dimitris Velaoras, Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie Microbienne (LOMIC), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Centre de Formation et de Recherche sur les Environnements Méditérranéens (CEFREM), Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), ANR-10-EQPX-0040,NAOS,Observations de l'océan global pour l'étude et la prévision de l'océan et du climat: préparation de la nouvelle décennie d'Argo(2010), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), and Université de Perpignan Via Domitia (UPVD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, 01 natural sciences, Eastern mediterranean, chemistry.chemical_compound, Geophysics, Oceanography, Nitrate, chemistry, 13. Climate action, Phytoplankton, Spring (hydrology), General Earth and Planetary Sciences, Environmental science, 14. Life underwater, Surface layer, Argo, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: In the eastern Mediterranean Sea, satellites have observed events of spring surface‐chlorophyll increase in the Rhodes Gyre region recurring intermittently. Few in situ biogeochemical data, however, exist to confirm their consistency, elucidate their seasonal characteristics, or discriminate among the possible drivers. During the year 2018, an array of BGC‐Argo floats was deployed in the region, collecting the first‐ever annual time series of in situ profiles of biogeochemical parameters in this area. Their observations demonstrated that nitrates, driven by mixed‐layer dynamics, were available at surface from December 2018 onwards and could have sustained phytoplankton growth. Phytoplankton accumulation at the surface was observed by satellite only in March 2019 when the mixed‐layer depth shoaled. These findings confirm that blooms occurring before the start of seasonal stratification are not easily recorded by satellite observations and reaffirm the need to consolidate the BGC‐Argo network to establish time series of the evolution of biogeochemical processes. Plain Language Summary The Levantine Sea, the easternmost area of Mediterranean Sea, is considered one of the poorest oceans on the Earth in terms of abundance of phytoplankton, the microscopic organisms that fuel the marine food web. However, historical data and satellite maps of chlorophyll (the pigment that reveals phytoplankton presence in the water) show episodic increases in the concentration of this pigment in the area near the island of Rhodes. To elucidate the characteristics of these events, a set of six robotic instruments (i.e. the BGC‐Argo floats) was deployed in the Levantine Sea in 2018. A BGC‐Argo float is an autonomous, free‐floating instrument that makes oceanic observations over the first 2,000 meters of the water column on a regular basis. This article presents an analysis of the data collected by these six robots. They provided the very first annual time series of biogeochemical observations in area, including during winter, when ship and satellite data are hard to collect. Our results reveal the increase in phytoplankton occurring before the start of seasonal stratification, increase that is not easily recorded by satellite observations and reaffirm the need to consolidate the BGC‐Argo network to establish time series of the evolution of biogeochemical processes.
Published: 2021
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55. Recent progress in the study of fine-scale physical-biological coupling in the Mediterranean Sea

Author: Gérald Grégori, Bàrbara Barceló-Llull, Louise Rousselet, Stéphanie Barrillon, Lucie Bordois, Ananda Pascual, Roxane Tzortzis, Nagib Bhairy, Franck Dumas, Caroline Comby, Melilotus Thyssen, Anne Petrenko, Llyod Izard, Andrea Doglioli, Frédéric Cyr, Marc Tedetti, Pierre Garreau, Francesco d'Ovidio, Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Processus et interactions de fine échelle océanique (PROTEO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut Mediterrani d'Estudis Avancats (IMEDEA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Universidad de las Islas Baleares (UIB), Northwest Atlantic Fisheries Centre (NWAFC), Fisheries and Oceans Canada (DFO), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Scripps Institution of Oceanography (SIO - UC San Diego), University of California [San Diego] (UC San Diego), University of California (UC)-University of California (UC), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Scripps Institution of Oceanography (SIO), and University of California-University of California
Subjects: Mediterranean climate, Oceanography, Frontogenesis, Mediterranean sea, Eddy, 13. Climate action, Diurnal cycle, [SDE.MCG]Environmental Sciences/Global Changes, Phytoplankton, Mesoscale meteorology, Sampling (statistics), Environmental science, 14. Life underwater
Abstract: Trabajo presentado a la 23rd EGU General Assembly, celebrada online del 19al 30 de abril de 2021., The fine scales are defined here as oceanic dynamical features (eddies, fronts and filaments) generally induced by mesoscale interactions and frontogenesis, and often associated with intense vertical exchanges. These processes are characterized by horizontal scales of 1–10 km with a relatively short lifetime of days/weeks to months. This temporal scale is similar to that of many biological processes, such as, phytoplankton growth, suggesting a physical and biological coupling. Numerical simulations and satellite observations have allowed the characterization of this regime highlighting the role played by these fine scales on structuring the phytoplankton community. To better understand this coupling mechanism, physical and biological in situ measurements are necessary. However, the observations of fine scales remains challenging due to the difficulties of sampling at high spatio-temporal frequency (~km ~daily). Over the past few years, the Mediterranean Sea has become a lab for developing fine scale in situ strategies. Indeed, a series of campaigns using a satellite based adaptative and Lagrangian strategy coupled with a high-resolution physical-biological sampling, have been performed in order to follow and describe fine scale structures. Following this strategy, the PROTEVSMED-SWOT 2018 cruise has been leaded in the South of the Balearic Islands, with a particular attention to correlate the Lagrangian sampling with the temporal phytoplankton growth, in order to reconstruct the phytoplankton diurnal cycle. Multidisciplinary in situ sensors have allowed to identify a frontal area with a dynamic vertical circulation. Furthermore, the presence of two Atlantic waters, at different stages of mixing associated with various abundances of several phytoplankton groups, corroborated that fine scales must be dynamical barriers to transport, as previous modeling studies have proposed. In order to better understand fine scale mechanisms, the Protevs Gibraltar cruise was performed in the Strait of Gibraltar in October 2020. This region of study is characterized by an important exchange of Mediterranean and Atlantic waters, and also by an intense circulation that generates energetic processes, which make it a favorable place for the formation of fine scale structures. The new knowledge acquired with these studies paves the way to the future BIOSWOT-Med campaign planned for 2022 in the western Mediterranean Sea under the future SWOT satellite crossover tracks.
Published: 2021
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56. Characterization of fronts in the Western Mediterranean with a special focus on the North Balearic Front

Author: Barral, Quentin-Boris, Zakardjian, Bruno, Dumas, Franck, Garreau, Pierre, Testor, Pierre, Beuvier, Jonathan, Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Variabilité de l'Océan et de la Glace de mer (VOG), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Mercator Océan, Société Civile CNRS Ifremer IRD Météo-France SHOM, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)
Subjects: Western Mediterranean, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Annual variability, Deep water formation, Frontal detection, North Balearic Front, Seasonal variability, Eddies, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract: International audience; We focus on the characterization of thermohaline fronts in the Western Mediterranean, with a particular focus on the North Balearic Front (NBF), separating the Atlantic Waters that spread into the Algerian Basin from the saltier and colder waters of the Liguro-Provençal area. We use a simple gradient-based method of front detection applied to a 20-year (from June 1993 to June 2013) reanalysis of the Mediterranean. Statistics of daily frontal indices are used to identify areas of recurrent fronts, i.e., frontal zones. Comparisons with data from glider transects and remotely sensed sea surface temperature and altimetry data have been used to validate our approach from daily to seasonal and interannual time scales. Our method yielded two co-existing frontal zones in the area of the NBF. One with an almost permanent haline surface frontal zone extending southeastward from the Balearic Islands to Sardinia, representing the northern limit of the fresher Atlantic Water that spreads via instabilities of the Algerian Current and associated Algerian Eddies. Between years, its position shifts by about 1° of latitude, possibly due to processes associated with both the deep water formation in the Provençal Basin and the spreading of southern Algerian Eddies. The second frontal zone is seasonal and thermally driven extending off the northeast of Menorca to the northwest of Corsica. The Pyrenees Front, a sharp thermal front off Cap de Creus which marks the boundary between the warm surface waters of the Balearic Sea and the cooler waters in the Gulf of Lion in late summer, appears to facilitate the formation of the aforementioned seasonal thermal front through the northeastward advection of its waters toward the West Corsican Current. The divergent eastward extensions of the two frontal zones, and their differences in nature, structure, and spatio-temporal variability, call for a revisit of the NBF appellation and a clarification of its dynamics.; Nous nous concentrons sur la caractérisation des fronts thermohalins en Méditerranée occidentale, avec un accent particulier sur le Front Nord-Baléares (NBF), séparant les eaux atlantiques qui se répandent dans le bassin algérien des eaux plus salées et plus froides de la zone Liguro-Provençal. Nous utilisons une méthode simple de détection des fronts basée sur le gradient, appliquée à une réanalyse de 20 ans (de juin 1993 à juin 2013) de la Méditerranée. Les statistiques des indices frontaux quotidiens sont utilisées pour identifier les zones de fronts récurrents, c'est-à-dire les zones frontales. Des comparaisons avec des données issues de transects de planeurs et des données de température de surface de la mer et d'altimétrie télédétectées ont été utilisées pour valider notre approche, de l'échelle journalière à l'échelle saisonnière et interannuelle. Notre méthode a permis d'identifier deux zones frontales coexistantes dans la région du NBF. L'une avec une zone frontale de surface haline quasi permanente s'étendant vers le sud-est des Baléares à la Sardaigne, représentant la limite nord des eaux atlantiques plus fraîches qui se répandent via les instabilités du courant algérien et des tourbillons algériens associés. D'une année sur l'autre, sa position se déplace d'environ 1° de latitude, probablement en raison de processus associés à la fois à la formation d'eau profonde dans le bassin provençal et à la propagation des tourbillons algériens du sud. La deuxième zone frontale est saisonnière et thermique, s'étendant du nord-est de Minorque au nord-ouest de la Corse. Le Front des Pyrénées, un front thermique net au large du Cap de Creus qui marque la limite entre les eaux chaudes de surface de la mer des Baléares et les eaux plus froides du Golfe du Lion à la fin de l'été, semble faciliter la formation du front thermique saisonnier susmentionné par l'advection de ses eaux vers le nord-est du courant de Corse occidentale. Les extensions divergentes vers l'est des deux zones frontales, et leurs différences de nature, de structure et de variabilité spatio-temporelle, appellent à une révision de l'appellation NBF et à une clarification de sa dynamique.
Published: 2021
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57. Integrating user preferences in the automatic quality assessment of hydrographic surveys

Author: Khannoussi, Arwa, Le Deunf, Julian, Meyer, Patrick, Lecornu, Laurent, Puentes, John, Meyer, Patrick, Entrepôts, Représentation et Ingénierie des Connaissances (ERIC), Université Lumière - Lyon 2 (UL2)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Equipe DECIDE (Lab-STICC_DECIDE), Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT), Département Logique des Usages, Sciences sociales et Sciences de l'Information (IMT Atlantique - LUSSI), IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), and Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)
Subjects: [INFO.INFO-AI] Computer Science [cs]/Artificial Intelligence [cs.AI], [INFO.INFO-DM] Computer Science [cs]/Discrete Mathematics [cs.DM], [INFO.INFO-RO] Computer Science [cs]/Operations Research [cs.RO], explainability, user preferences, [INFO.INFO-RO]Computer Science [cs]/Operations Research [cs.RO], [INFO.INFO-DM]Computer Science [cs]/Discrete Mathematics [cs.DM], MR-Sort, [INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI], Quality assessment
Abstract: International audience; The goal of hydrographic surveys is to measure and describe features which affect maritime navigation, marine construction, dredging, and other human activities at sea. These surveys serve among other thing to create nautical charts. The International Hydrographic Organization (IHO) published recently an update of the Standards for Hydrographic Surveys. It shows how important data quality is for these surveys, by setting new standards which allow to refine the data quality levels of criteria according to stated hydrographic needs. This means that depending on the final use of a survey, its quality could be perceived differently by users. It follows from this that, evaluating the quality of a survey, while taking into account the needs of a the end user, as well as automating this evaluation, are real issues. Next to that, data and information quality are classically examined through multiple dimensions. The choice of these dimensions, as well as their relative importance in the overall assessment of the quality, do obviously depend again on the end user. These dimensions might also be influenced by the context of the survey, which in turn might be perceived differently by each user, and therefore modeled in various ways. Given the many elements that impact the quality of hydrographic surveys, we consider the following research question: How to integrate the end user's perception of the quality of a survey with the quality of the acquisition conditions, while guaranteeing a traceable and explainable overall assessment of the survey ? To answer this question, we propose a process which first uses data quality analysis techniques to automatically determine, from data and metadata, various quality measures of hydrographic surveys, and combine these with an MR-Sort preference model to integrate various user profiles into the overall assessment. We show that these multiple quality dimensions (or criteria), combined with different user profiles (acoustician, cartographer, etc.), can lead to different overall evaluations of the quality of hydrographical surveys. Last but not least, we show how these combined tools can lead to explainable outputs, which can be used to analyse existing surveys, and make recommendations to improve future ones.
Published: 2021

58. Detection and tracking of mesoscale eddies in the Mediterranean Sea: A comparison between the Sea Level Anomaly and the Absolute Dynamic Topography fields

Author: Cori Pegliasco, Rosemary Morrow, Franck Dumas, Alexis Chaigneau, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Service Hydrographique et Océanographique de la Marine (SHOM), and Ministère de la Défense
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Mesoscale meteorology, Aerospace Engineering, 01 natural sciences, Mediterranean sea, Mesoscale eddies, 0103 physical sciences, Mediterranean Sea, Bathymetry, Sea level, Altimeter, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Orographic lift, Astronomy and Astrophysics, Ocean surface topography, Geophysics, Eddy, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Climatology, Spatial ecology, General Earth and Planetary Sciences, Altimetry, Geology
Abstract: International audience; Mediterranean Sea eddies are often generated in fixed geographical locations linked to either bathymetric fluctuations, coastline changes, instabilities around islands, or orographic wind forcing. Because of that, the mean circulation exhibits features with the same special scales as the mesoscale field. We provide here a first comparison of eddies detected and tracked using two altimetry products, the Sea Level Anomaly (SLA) and the Absolute Dynamic Topography (ADT), from 2000 to 2015. We showed that more individual eddies and trajectories are detected in the SLA data than in the ADT, having larger radius but lower Eddy Kinetic Energy. The spatial distribution of the mesoscale activity is different between the two data sets: the ADT-detected eddies closely follow the Mean Dynamic Topography (MDT) patterns which include the mean eddy generation sites whereas the SLA-detected eddies show more spatial homogeneity. The larger eddies are generally well detected in both the ADT or the SLA fields, but the numerous smaller and coastal eddies detected in the SLA fields have a tendency to mismatch the ADT detected eddies. Only 20-30% of eddies are detected exclusively in the SLA or the ADT product (i.e. have no collocation in the other field), whereas to 65-80% of the eddies are detected both in the SLA and the ADT fields. The Ierapetra Eddy is a typical example of the limitation of the SLA-detected eddies, as this orographically controlled feature is present in the MDT and thus leads to an artificial cyclonic eddy in the SLA field that shifts around its most frequent position. This study recommends the use of ADT fields for the detection of mesoscale structures in the Mediterranean Sea where the mean circulation and these mesoscale features have the same spatial scale and intensity, and similarly for any other ocean regions where the MDT contains mesoscale patterns. Yet the ADT fields depend on the accuracy of the MDT, and the altimeter-based SLA fields may be preferable in specific locations where the MDT is not reliable.
Published: 2021
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59. Creation of topographic knowledge bases from heterogeneous sources

Author: Rawsthorne, Helen Mair, Rawsthorne, Helen, Laboratoire sciences et technologies de l'information géographique (LaSTIG), Ecole des Ingénieurs de la Ville de Paris (EIVP)-École nationale des sciences géographiques (ENSG), Institut National de l'Information Géographique et Forestière [IGN] (IGN)-Université Gustave Eiffel-Institut National de l'Information Géographique et Forestière [IGN] (IGN)-Université Gustave Eiffel, Service hydrographique et océanographique de la Marine (Shom), Institut national de l'information géographique et forestière (IGN), and Ecole Nationale des Sciences Géographiques (ENSG)
Subjects: geographic knowledge base, [INFO]Computer Science [cs], base de connaissances géographiques, [INFO] Computer Science [cs]
Abstract: International audience; Ma thèse vise à proposer une approche pour construire, peupler et évaluer une base de connaissances géoréférencées à partir de sources hétérogènes, notamment des bases de données vectorielles et des textes. Celles-ci doivent permettre d’intégrer à la fois du référencement spatial direct et indirect pour le développement d’applications nécessitant de faire du raisonnement spatial selon ces deux modalités. La première étude de cas dans cette thèse se base sur les Instructions Nautiques du Service hydrographique et océanographique de la Marine (Shom). Ce sont des ouvrages publiés par le Shom qui aident à la navigation côtière en complément des cartes nautiques pour planifier un itinéraire. Principalement, elles décrivent le paysage côtier depuis le point de vue d'un navire et donnent des indications pour naviguer près de la côte et accéder aux ports.Notre objectif premier est donc d’extraire, géoréférencer et structurer les connaissances contenues dans ces Instructions Nautiques : les entités spatiales, les relations spatiales et les instructions liées à la navigation côtière. Le but est de rendre les connaissances contenues dans ces ouvrages, qui sont actuellement écrits et mis à jour à la main, structurées et réutilisables dans une base de connaissances avec l'aide d'une ontologie. Ce poster présente l’approche globale envisagée ainsi qu’une première version de cette ontologie.
Published: 2021

60. Seismo-acoustic wave propagation in the Rade of Hyères (France) generated by counter-mining of explosive devices : risk assessment from the comparison between numerical simulations and real experiments

Author: Favretto-Cristini, Nathalie, Wang, Fang, Garlan, Thierry, Morio, Olivier, Deschamps, Anne, Ambrois, David, Mercerat, Diego, Demoulin, Xavier, Beucler, Éric, Bonnin, Mickaël, Cristini, Paul, Monteiller, Vadim, Laboratoire de Mécanique et d'Acoustique [Marseille] (LMA ), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM), Shenzhen University [Shenzhen], Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Centre d'études et d'expertise sur les risques, l'environnement, la mobilité et l'aménagement - Equipe-projet Repsody (Equipe-projet Repsody), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Auteur indépendant, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire des Sciences de l'Univers Nantes Atlantiques (OSUNA), Université d'Angers (UA)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université Gustave Eiffel, Ondes et Imagerie (O&I), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Université d'Angers (UA)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Conservatoire National des Arts et Métiers [CNAM] (CNAM), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), and Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS.MECA.VIBR]Physics [physics]/Mechanics [physics]/Vibrations [physics.class-ph], underwater acoustics, interface waves, seismics, 13. Climate action, counter-mining, 14. Life underwater, [PHYS.MECA.ACOU]Physics [physics]/Mechanics [physics]/Acoustics [physics.class-ph]
Abstract: International audience; Explosive devices from World War II are discovered almost every week on the French coasts and they must be destroyed by the French Navy Mine Warfare Office. The consequences of the counter-mining on the marine environment are complex to evaluate. Depending on the environment geology, the explosive charges and their localization, the seismo-acoustic waves generated by the explosion may cause damage to infrastructures located on the coast, and under specific conditions small submarine landslides. The ANR ASTRID POSA project proposed to address the risk assessment issue on the Mediterranean coast. The main originality of this project lied in the approach used that combines geological measurements, acoustic data recorded within the sea coastal zone and seismic data recorded on the coast, together with numerical simulations of seismo-acoustic wave propagation. We propose here to present the results of such a methodology applied to the counter-mining campaign that occurred in the Rade of Hyères (France) in December 2018. We focus more specifically on the numerical simulations of seismo-acoustic wave propagation from the location of the device explosion to several seismometers deployed on the coast of Hyères. From topographical and sedimentary measurements performed in the Rade of Hyères, physical and geometrical characteristics of the marine seabed have been carefully selected as input data for numerical simulations. In addition, a particular attention has been paid to the measured characteristics of the device explosion (source). The numerical simulations have then been conducted using a spectral-element method. The impact of the explosive device charge and its location (on the seabed or in the water column), together with the impact of the marine environment properties, on the simulated signals have been studied. Finally, the numerical results have been compared with the real signals recorded by the seismometers. The risks of land degradation have been evaluated afterwards.
Published: 2020
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61. Preparing the New Phase of Argo: Technological Developments on Profiling Floats in the NAOS Project

Author: Xavier André, Pierre-Yves Le Traon, Serge Le Reste, Vincent Dutreuil, Edouard Leymarie, Damien Malardé, Claudie Marec, Jérôme Sagot, Martin Amice, Marcel Babin, Hervé Claustre, Arnaud David, Fabrizio D’Ortenzio, Nicolas Kolodziejczyk, José Luis Lagunas, Marc Le Menn, Bertrand Moreau, David Nogré, Christophe Penkerc’h, Antoine Poteau, Corentin Renaut, Christophe Schaeffer, Vincent Taillandier, Virginie Thierry, Takuvik Joint International Laboratory ULAVAL-CNRS, Université Laval [Québec] (ULaval)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Mercator Océan, Société Civile CNRS Ifremer IRD Météo-France SHOM, Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Terre et Environnement de Lorraine (OTELo), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université Laval [Québec] (ULaval)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Meteorology, lcsh:QH1-199.5, Ocean Engineering, profiling float, Aquatic Science, float technology, lcsh:General. Including nature conservation, geographical distribution, Oceanography, 01 natural sciences, under-ice, biogeochemistry, Profiling (information science), 14. Life underwater, lcsh:Science, Argo, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Water Science and Technology, Global and Planetary Change, 010604 marine biology & hydrobiology, ocean, Arctic, deep, [SDE]Environmental Sciences, global observing system, Environmental science, lcsh:Q
Abstract: International audience; The international array of profiling floats known as Argo is a major component of the global ocean-and climate-observing system. In 2010, the NAOS (Novel Argo Observing System) project was selected as part of France's Equipex "Investissement d'Avenir" program. The objectives of NAOS were to consolidate the French contribution to the Argo core mission (global temperature and salinity measurements down to 2,000 m) as well as to develop the future generation of French Argo profiling floats and prepare the next phase of the Argo program with an extension to the deep ocean (Deep-Argo), biogeochemistry (BGC-Argo) and polar seas. This paper summarizes the main technological advances and at-sea validations carried out as part of NAOS: development of a deep (4,000 m) float, a new BGC float for Research & Development (R&D) applications, and a BGC float for deployments in Arctic areas, assessment of a new density and Absolute Salinity optical sensor, improvement of the reliability of the standard Argo float, and upgraded satellite-transmission performance. French profiling floats developed in this way are now operational and among the most deployed worldwide, and the density sensor is the most promising of its kind for profiling floats applications.
Published: 2020
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62. Tridimensional nonhydrostatic transient rip currents in a wave-resolving model

Author: Laurent Debreu, Franck Dumas, Rachid Benshila, Patrick Marchesiello, James C. McWilliams, Francis Auclair, Rafael Almar, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire d'aérologie (LA), Université Fédérale Toulouse Midi-Pyrénées, Mathematics and computing applied to oceanic and atmospheric flows (AIRSEA), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Grenoble Alpes (UGA)-Laboratoire Jean Kuntzmann (LJK), Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Department of Atmospheric and Oceanic Sciences [Los Angeles] (AOS), University of California [Los Angeles] (UCLA), University of California-University of California, Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, This research has received support from a consortium of French research agencies, as part of CROCO’s development project (GdR CROCO). It was granted access to the HPC resources of CALMIP supercomputing center under allocation P19069. The fieldwork received support by the French INSU/EC2CO program (Grand Popo Experiment). We also thank H. Michallet for sharing the GLOBEX data, now freely available at zenodo.org/record/4009405. Apart from these, all data were acquired by the authors and the CROCO source code is freely available at www.croco-ocean.org. Both observational and modeling data are available upon request., Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'aérologie (LAERO), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), University of California (UC)-University of California (UC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Centre National de la Recherche Scientifique (CNRS), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Grenoble Alpes [2020-....] (UGA [2020-....])-Laboratoire Jean Kuntzmann (LJK), Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2020-....] (UGA [2020-....])-Institut polytechnique de Grenoble - Grenoble Institute of Technology [2020-....] (Grenoble INP [2020-....]), Université Grenoble Alpes [2020-....] (UGA [2020-....])-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology [2020-....] (Grenoble INP [2020-....]), Université Grenoble Alpes [2020-....] (UGA [2020-....]), Laboratoire de physique hydrodynamique et sédimentaire (DYNECO/PHYSED), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Mathematics and computing applied to oceanic and atmospheric flows [2020-....] (AIRSEA [2020-....]), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Grenoble Alpes [2020-....] (UGA [2020-....])-Laboratoire Jean Kuntzmann [2020-....] (LJK [2020-....]), and Université Grenoble Alpes [2020-....] (UGA [2020-....])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut polytechnique de Grenoble - Grenoble Institute of Technology [2020-....] (Grenoble INP [2020-....])
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Oceanography, 01 natural sciences, Instability, Physics::Fluid Dynamics, Computer Science (miscellaneous), wave-resolving model, 14. Life underwater, transient rip, Physics::Atmospheric and Oceanic Physics, Rip current, 0105 earth and related environmental sciences, Surfzone, 010505 oceanography, Turbulence, Turbulent cascade, Breaking wave, Rip currents, 3D instability, Wave-resolving LES model, Mechanics, Vorticity, Geotechnical Engineering and Engineering Geology, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, Eddy, Free surface, Energy cascade, Geology, nonhydrostatic
Abstract: International audience; Flash rips and surf eddies are transient horizontal structures of the order of 10 to 100 m, which can be generated in the surfzone in the absence of bathymetric irregularities. They are traditionally evaluated in a depth averaged setting which involves intrinsic horizontal shear instabilities and the direct generation of vorticity by short-crested waves. In this article, we revisit the processes of surf eddy generation with a new three-dimensional wave resolution model (CROCO) and provide a plausible demonstration of new 3D non-hydrostatic instability and turbulent cascade. We first present a quick overview of a compressible free surface approach suitable for nearshore dynamics. Its ability to simulate the propagation of surface gravity waves and nearshore wave-driven circulation is validated by two laboratory experiments. Next, we present a real world application from Grand Popo Beach, Benin, forced by waves with frequency and directional spreading. The generation of surf eddies by the 3D model differs from depth-averaged models, due to the vertical shear associated with shallow breaking waves. In this case, the generation of eddies from both horizontal shear instability and the breaking of short-crested waves is hampered, the former by stretching the along shore current and the latter by inhibiting the inverse energy cascade. Instead, the vertical shear flow is subjected to forced wave group variability and Kelvin-Helmholtz type instability at an inflection point. Primary and secondary instabilities generate spanwise and streamwise vorticity connecting small-scale eddies to larger horizontal surfzone structures. Streamwise filaments, appearing as 5 m wide ribs or mini-rips, can extend beyond the surfzone but with moderate energy. These results appear consistent with the velocity spectra and observed patterns of tracers and suspended sediments at Grand Popo Beach. The timescale associated with the mean shear-induced turbulence is several times the wave period and suggests an intermediate range between breaker-induced turbulence and large-scale surf eddies.
Published: 2020
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63. Transferencia de conocimientos hidrográficos y astronómicos entre Francia y Argentina. La construcción de paisajes marítimos y portuarios

Author: Miguel de Marco (h), Nathan Godet, Helen Mair Rawsthorne, Núcleo de Estudios Históricos de las Ciudades Portuarias Regionales, Instituto de Estudios Históricos, Económicos, Sociales e Internacionales (IDEHESI), Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET), Centre de Recherche Interdisciplinaires en Histoire, Histoire de l'Art et Musicologie (CRIHAM), Institut Sciences de l'Homme et de la Société (IR SHS UNILIM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Université de Poitiers, Centre François Viète - Brest (CFV UBO), Centre François Viète : épistémologie, histoire des sciences et des techniques - EA1161 (CFV), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Université de Brest (UBO)-Université de Nantes - UFR Lettres et Langages (UFRLL), Université de Nantes (UN)-Université de Nantes (UN)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut Brestois des Sciences de l'Homme et de la Société (IBSHS), Université de Brest (UBO), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Maison des sciences de l'Homme d'Aquitaine (MSHA), Université Bordeaux Montaigne-Centre National de la Recherche Scientifique (CNRS), Institut Brestois des Sciences de l'Homme et de la Société (IBSHS), Université de Brest (UBO)-Université de Brest (UBO)-Centre François Viète : épistémologie, histoire des sciences et des techniques - EA1161 (CFV), Université de Nantes (UN)-Université de Nantes (UN)-Université de Nantes - UFR Lettres et Langages (UFRLL), and Université de Nantes (UN)-Université de Nantes (UN)
Subjects: Ciencia, Franco-Argentine cooperation, Cooperation franco argentina, ports, Cooperación franco argentina, history, [SHS.HIST]Humanities and Social Sciences/History, Patrimonio, Puertos, science, Historia, heritage, [SHS]Humanities and Social Sciences
Abstract: short; International audience; The Hydrographic and Oceanographic Service of the French Navy (Shom), based in the city of Brest, has held one of the most important documentary repositories in its field for 300 years. A graduate of the Naval School of the same city in the mid-19th century, Francisco Beuf, played a leading role in the beginnings of the Argentine Naval Hydrographic Service and the Argentine Naval School, where he settled at a time when the two countries’ governments became closer, around 1880. This paper aims to contribute to the understanding of the transfer of hydrographic and astronomical knowledge, cultivated for centuries in France, to Argentina through two instances: Beuf’s establishment within the alliance ofactors from science, politics and the French navy with the purpose of sustaining international leadership, and the cooperation established between both governments during the scientific expedition of the French ship La Romanche in 1882 to Patagonia and Tierra del Fuego. The relevance of this type of comparative approach to the knowledge of the dynamics of interaction between the elites of port cities and the cultural and heritage formation of port landscapes is also highlighted.; El Servicio Hidrográfica y Oceanográfica de la Marina de Francia (Shom), con sede en la ciudad de Brest, desde hace 300 años atesora uno de los repositorios documentales más importantes en su temática. Un egresado de la Escuela Naval de esa misma ciudad a mediados del siglo XIX, Francisco Beuf, tuvo un rol protagónico en los inicios del Servicio de Hidrografía Naval y la Escuela Naval de Argentina, en la que se radicó en un momento de acercamiento entre los gobiernos ambos países, hacia 1880. La ponencia pretende contribuir al conocimiento de la transferencia de conocimientos de Hidrografía y Astronomía cultivados durante siglos en Francia hacia la Argentina a través de dos instancias: la radicación de Beufen el marco de la alianza de actores de las ciencias, la política y la armada francesa con el propósito de sostener un liderazgo internacional, y la cooperación establecida entre ambos gobierno con motivo de la expedición científica del buque francés La Romanche en 1882 a la Patagonia y Tierra del Fuego. Asimismo se pone en valor la pertinencia de este tipo de enfoques comparados para el conocimiento de la dinámica de interacción entre las elites de las ciudades portuarias, y la conformación patrimonial y cultural de los paisajes portuarios.
Published: 2020

64. Large time step TVD IMEX Runge-Kutta schemes based on arbitrarily high order Butcher tableaux

Author: Michel-Dansac, Victor, Thomann, Andrea, TOkamaks and NUmerical Simulations (TONUS), Institut de Recherche Mathématique Avancée (IRMA), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Inria Nancy - Grand Est, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Institut für Mathematik [Mainz], Johannes Gutenberg - Universität Mainz (JGU), Service Hydrographique et Océanographique de la Marine (SHOM), INDAM-DP-COFUND-2015, grant number 713485, European Project: 713485,H2020,H2020-MSCA-COFUND-2015,INdAM-DP-COFUND-2015(2017), Dipartimento di Scienze e Alta Tecnologia, and Università degli Studi dell’Insubria
Subjects: L∞ stability, MOOD, MSC : 65M06 · 65M08 · 65M12, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], IMEX RK schemes, hyperbolic multi-scale equations, Computer Science::Numerical Analysis, TVD, [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA], Mathematics::Numerical Analysis
Abstract: The context of this work is the development of large time step TVD IMEX Runge-Kutta schemes to approximate the solution of hyperbolic multi-scale equations. A key feature of our newly proposed TVD schemes is that the resulting CFL condition does not depend on the large-scale eigenvalues of the multi-scale PDE, as long as they are treated implicitly. However, a result from Gottlieb et al. [15] states that unconditionally stable implicit TVD or L∞ stable RK schemes can only be of first order. We show that this result is also valid for IMEX-RK schemes, which have a CFL restriction only depending on the explicitly treated scales. Therefore, the goal of this work is to improve the precision of a first-order IMEX-RK scheme, while retaining its L∞ stability and TVD properties. In this work we extend and generalize the approach introduced in [9] based on a convex combination between a first-order TVD IMEX Euler scheme and a potentially oscillatory high-order IMEX-RK scheme. We derive and analyse the method for a scalar multi-scale equation and we numerically assess the performance of our TVD schemes compared to standard L-stable and SSP IMEX RK schemes from the literature. Finally, we combine our TVD schemes with the MOOD framework to increase their applicability. For numerical validation, we apply the schemes to the isentropic Euler equations and compare the results with [9] where a second order scheme is used as a basis of the TVD scheme.
Published: 2020

65. Bruit sous-marin

Author: RECUERO VIRTO, LAURA, Dumez, Hervé, Galichon, Pascal, Courtois, Florent Le, Muntoni, Manuel, Centre de recherche en gestion i3 (i3-CRG), École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Grand port maritime du Havre, Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, and Groupement d’intérêt publique Seine-Aval (GIP Seine-Aval)
Subjects: [SHS.GESTION]Humanities and Social Sciences/Business administration, [SHS]Humanities and Social Sciences
Abstract: Directeur de publication : Denis Bailly; International audience; L’impact du bruit sous-marin sur la vie marine suscite de plus en plus d’inquiétudes, en raison de l’augmentation constante du nombre et de la diversité des activités humaines en mer. En particulier, les niveaux de bruit chroniques provenant de la navigation commerciale ont augmenté de manière significative au cours des 60 dernières années et ils devraient continuer à augmenter dans les années à venir. En réponse à cette préoccupation, les Nations Unies ont signé un engagement volontaire pour réduire le bruit sousmarin (#OceanAction18553), qui reconnaît l’impact négatif que le bruit de la navigation peut avoir sur la vie marine. Dans ce policy brief, nous examinons le rôle des ports dans la réduction de ce type de bruit et illustrons nos résultats à l’aide du cas d’étude du port du Havre.
Published: 2020

66. Bruit sous-marin: Que pouvons-nous apprendre de l’étude de cas du port du Havre ?

Author: RECUERO VIRTO, LAURA, Dumez, Hervé, Galichon, Pascal, Courtois, Florent Le, Muntoni, Manuel, Centre de recherche en gestion i3 (i3-CRG), École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Grand port maritime du Havre, Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, and Groupement d’intérêt publique Seine-Aval (GIP Seine-Aval)
Subjects: [SHS.GESTION]Humanities and Social Sciences/Business administration, [SHS]Humanities and Social Sciences
Abstract: Directeur de publication : Denis Bailly; International audience; L’impact du bruit sous-marin sur la vie marine suscite de plus en plus d’inquiétudes, en raison de l’augmentation constante du nombre et de la diversité des activités humaines en mer. En particulier, les niveaux de bruit chroniques provenant de la navigation commerciale ont augmenté de manière significative au cours des 60 dernières années et ils devraient continuer à augmenter dans les années à venir. En réponse à cette préoccupation, les Nations Unies ont signé un engagement volontaire pour réduire le bruit sousmarin (#OceanAction18553), qui reconnaît l’impact négatif que le bruit de la navigation peut avoir sur la vie marine. Dans ce policy brief, nous examinons le rôle des ports dans la réduction de ce type de bruit et illustrons nos résultats à l’aide du cas d’étude du port du Havre.
Published: 2020

67. The Alderney Race: general hydrodynamic and particular features

Author: Lucille Furgerot, Anne-Claire Bennis, Franck Dumas, Yann Méar, C Voiseux, Mehdi Morillon, Emmanuel Poizot, Pascal Bailly du Bois, PSE-ENV/SRTE/LRC, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Laboratoire Universitaire des Sciences Appliquées de Cherbourg (LUSAC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU), Morphodynamique Continentale et Côtière (M2C), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: model, General Mathematics, 0211 other engineering and technologies, General Engineering, General Physics and Astronomy, 02 engineering and technology, Articles, 010501 environmental sciences, 01 natural sciences, current, Current (stream), Race (biology), [SDU]Sciences of the Universe [physics], Alderney Race, hydrodynamics, tide, La Hague Cape, 14. Life underwater, 021108 energy, Geology, Physics::Atmospheric and Oceanic Physics, Research Articles, 0105 earth and related environmental sciences, Marine engineering
Abstract: This study presents an overview of the main hydrodynamic features of the Alderney Race strait based on in situ measurements and two-dimensional hydrodynamic model simulations. The strait encompasses a large amplitude of tidal properties (tidal range and tidal wave propagation) and particularly strong currents exceeding 5 m s −1 with associated counter currents and gyres. Variations in depth, sea bottom roughness, coastal topography and current orientation around the La Hague Cape provide access to a large variety of original hydrodynamic regimes. Some are revealed as locations with a 0.4 m drop in the mean sea level associated with strong average currents. A resonance effect associated with the offshore currents can also be observed close to the coasts. The ‘St Martin whistle’ occurs in a bay whose gyre centre oscillates with a reversal of the measured current every 5–7 min. The Alderney Race represents a particular area of interest for coastal hydrodynamic studies. The available in situ measurement datasets are rich with recordings of: sea levels; acoustic Doppler current profiler current profiles; surface radar currents; waves; dye experiments; surface and in-depth dissolved tracer surveys. Combined with hydrodynamic models, the complexity of this area can be further understood and knowledge of the hydrodynamic process and forcing parameters can be refined, which can be applied to other coastal areas. This article is part of the theme issue ‘New insights on tidal dynamics and tidal energy harvesting in the Alderney Race’.
Published: 2020
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68. Analyse des transports spécifiques des masses d'eau en Méditerranée occidentale dans la réanalyse de vingt et un ans de MEDRYS1V2

Author: Pierre Garreau, Franck Dumas, Bruno Zakardjian, Jonathan Beuvier, Quentin-Boris Barral, Université de Toulon (UTLN), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Mercator Océan, Société Civile CNRS Ifremer IRD Météo-France SHOM, Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)
Subjects: Salinity, Mediterranean climate, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Water mass, Oceanography, Mediterranean sea, Potential density, Outflow, 14. Life underwater, Transect, Surface water, Geology, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract: International audience; We present an analysis of specific water masses fluxes in the Western Mediterranean Sea issued from a twenty years (1992-2013) reanalysis (MEDRYS1V2). Water masses are identified on the base of salinity and potential density properties and computes; the fractions of each water mass involved in total flux are computed under the hypothesis assumptions of mixing lines schemes. It was first designed in order to avoid rough truncations between water masses on the T-S diagram when using fixed thermo-haline properties thresholds. The method does not use the temperature marker due to its high seasonal variability in near surface waters (0-200 m) and we consider that potential density is a better marker to discriminate deep and intermediate water masses. The algorithm discriminates successively five different water masses : the Atlantic Water (AW) incoming from the Gibraltar strait (salinity between 36,1 and 38,45 PSU), the Levantine Intermediate Waters (LIW) incoming from the Tunisia-Sicily strait (salinity between 38,45 and 39.1 PSU), the Modified Atlantic Waters (MAW) defined as near-surface waters (potential density less than 28,9 kg m-3) that are neither AW or LIW, while Western Intermediate Waters (WIW) are those remaining until the sigma(theta) = 29,10 kg m-3 threshold for Western Mediterranean Deep Waters (WMDW) is reached. Such computed fractions of each water mass, whose sum is constrained to unity, are then used to compute their water masses transports all along over twenty years of the reanalysis. The transport are assessed across computed on key transects delimiting known sub-basin entities (Ligurian Sea, Gulf of Lion, Balearic Sea...), with total transports showing balanced mass budget. The such computed total transport reveal marked differences in their seasonal to interannual variability, while the analysis of the water mass transports allows to identify those which mainly implied induced these variability. The results first show a low seasonal and no significant interannual variability at the exit of the Alboran Sea that results from the balance between the eastward AW/MAW outflow and the westward WIW and WMDW inflows. The Corsican strait, the Ligurian Sea line and Tunisia-Sardinia straits show a marked seasonal variability (0,37-0,39 Sv) mainly driven by the AW/MAW. By contrast, a strong interannual variability dominates the seasonal one (-2 to 1 Sv) between the Algerian Basin and the northern basin, correlated to the WMDW formation. The analysis of each specific water masses transport pointed out that shows this marked variability to be first driven by the intermediate and deep water masses transports. Similarly the interannual variability of the AW and MAW transports in the central part of the Western Mediterranean suggests some coupling between the deep, intermediate and surface water masses, even through the shallower Balearic Sea.; Nous présentons une analyse des flux de masses d'eau spécifiques dans la mer Méditerranée occidentale issus d'une réanalyse sur vingt ans (1992-2013) (MEDRYS1V2). Les masses d'eau sont identifiées sur la base des propriétés de salinité et de densité potentielle et calculées ; les fractions de chaque masse d'eau impliquées dans le flux total sont calculées sous les hypothèses des schémas de lignes de mélange. Cette méthode a été initialement conçue pour éviter les troncatures grossières entre les masses d'eau sur le diagramme T-S lors de l'utilisation de seuils fixes de propriétés thermo-halines. La méthode n'utilise pas le marqueur de température en raison de sa grande variabilité saisonnière dans les eaux proches de la surface (0-200 m) et nous considérons que la densité potentielle est un meilleur marqueur pour discriminer les masses d'eau profondes et intermédiaires. L'algorithme discrimine successivement cinq masses d'eau différentes : les eaux atlantiques (AW) provenant du détroit de Gibraltar (salinité entre 36,1 et 38,45 PSU), les eaux intermédiaires du Levant (LIW) provenant du détroit de Tunisie-Sicile (salinité entre 38,45 et 39. 1 PSU), les eaux atlantiques modifiées (MAW) définies comme des eaux proches de la surface (densité potentielle inférieure à 28,9 kg m-3) qui ne sont ni AW ni LIW, tandis que les eaux intermédiaires occidentales (WIW) sont celles qui restent jusqu'à ce que le seuil sigma(theta) = 29,10 kg m-3 pour les eaux profondes de la Méditerranée occidentale (WMDW) soit atteint. Ces fractions calculées de chaque masse d'eau, dont la somme est contrainte à l'unité, sont ensuite utilisées pour calculer les transports de leurs masses d'eau tout au long des vingt années de la réanalyse. Les transports sont évalués à travers les calculs sur des transects clés délimitant des entités de sous-bassins connues (mer Ligure, golfe du Lion, mer Baléares...), avec des transports totaux montrant un bilan de masse équilibré. Les transports totaux ainsi calculés révèlent des différences marquées dans leur variabilité saisonnière et inter-annuelle, tandis que l'analyse des transports de masse d'eau permet d'identifier ceux qui ont principalement induit cette variabilité. Les résultats montrent d'abord une faible variabilité saisonnière et une variabilité inter-annuelle non significative à la sortie de la mer d'Alboran qui résulte de l'équilibre entre le flux sortant AW/MAW vers l'est et les flux entrants WIW et WMDW vers l'ouest. Le détroit de Corse, la ligne de la mer Ligure et les détroits de Tunisie et de Sardaigne présentent une variabilité saisonnière marquée (0,37-0,39 Sv) principalement due à l'AW/MAW. En revanche, une forte variabilité inter-annuelle domine la variabilité saisonnière (-2 à 1 Sv) entre le bassin algérien et le bassin nord, corrélée à la formation de l'WMDW. L'analyse de chaque transport spécifique de masses d'eau a montré que cette variabilité marquée est d'abord déterminée par les transports de masses d'eau intermédiaires et profondes. De même, la variabilité inter-annuelle des transports AW et MAW dans la partie centrale de la Méditerranée occidentale suggère un certain couplage entre les masses d'eau profondes, intermédiaires et de surface, même à travers la mer des Baléares, moins profonde.
Published: 2020
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69. Dissolved Radiotracers and Numerical Modeling in North European Continental Shelf Dispersion Studies (1982–2016): Databases, Methods and Applications

Author: Pascal Bailly du Bois, Franck Dumas, Claire Voiseux, Mehdi Morillon, Pierre-Emmanuel Oms, Luc Solier, PSE-ENV/SRTE/LRC, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Service Hydrographique et Océanographique de la Marine (SHOM), and Ministère de la Défense
Subjects: lcsh:TD201-500, English Channel, lcsh:Hydraulic engineering, data collection, modeling, tracer, lcsh:Water supply for domestic and industrial purposes, tritium (H-3), antimony 125 (Sb-125), lcsh:TC1-978, [SDE]Environmental Sciences, antimony 125 (125Sb), tritium (3H), dispersion, dispersion, Biscay Bay, North Sea, radionuclide
Abstract: Significant amounts of anthropogenic radionuclides were introduced in ocean waters following nuclear atmospheric tests and development of the nuclear industry. Dispersion of artificial dissolved radionuclides has been extensively measured for decades over the North-European continental shelf. In this area, the radionuclide measurement and release fluxes databases provided here between 1982 and 2016 represent an exceptional opportunity to validate dispersion hydrodynamic models. This work gives accessibility to these data in a comprehensive database. The MARS hydrodynamic model has been applied at different scales to reproduce the measured dispersion in realistic conditions. Specific methods have been developed to obtain qualitative and quantitative results and perform model/measurement comparisons. Model validation concerns short to large scales with dedicated surveys following the dispersion: it was performed within a two- and three-dimensional framework and from minutes and hours following a release up to several years. Results are presented concerning the dispersion of radionuclides in marine systems deduced from standalone measurements, or according to model comparisons. It allows characterizing dispersion over the continental shelf, pathways, transit times, budgets and source terms. This review presents the main approaches developed and types of information derived from studies of artificial radiotracers using observations, hydrodynamic models or a combination of the two, based primarily on the new featured datasets.
Published: 2020
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70. Combining remote sensing and in situ observations to study the physical-biological coupling at fine scale: recent Mediterranean campaigns and outlook

Author: Stéphanie Barrillon, Francesco d'Ovidio, Franck Dumas, Pierre Marrec, Jean-Luc Fuda, Gérald Grégori, Pierre Garreau, Francois Carlotti, Léo Berline, Marc Tedetti, Roxane Tzortzis, Nagib Bhairy, Melilotus Thyssen, Anne Petrenko, Frédéric Cyr, Louise Rousselet, Ananda Pascual, Andrea Doglioli, Lloyd Izard, Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Processus et interactions de fine échelle océanique (PROTEO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut Mediterrani d'Estudis Avancats (IMEDEA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Universidad de las Islas Baleares (UIB), Graduate School of Oceanography [Narragansett], University of Rhode Island (URI), Scripps Institution of Oceanography (SIO), University of California [San Diego] (UC San Diego), University of California-University of California, Northwest Atlantic Fisheries Centre (NWAFC), Fisheries and Oceans Canada (DFO), EGU, Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Scripps Institution of Oceanography (SIO - UC San Diego), and University of California (UC)-University of California (UC)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Biogeochemical cycle, Ecology (disciplines), Sampling (statistics), Mediterranean sea, Eddy, 13. Climate action, Phytoplankton, Environmental science, Marine ecosystem, 14. Life underwater, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Scale (map), Remote sensing
Abstract: on line; International audience; The oceanic fine scales are highly energetic features (eddies, fronts, meanders, filaments) with relatively short lifetimes (days/weeks to months). Due to their associated strong gradients in physical and biogeochemical properties, they crucially affect ocean physics and ecology with potential impacts at the climate scale. The temporal scale associated with these horizontal and vertical fine scales is the same as many important ecological processes including phytoplankton growth and competition. This temporal resonance is one of the reasons behind the fine-scale variability appearing in the marine ecosystems structure and related domains, including biogeochemical cycles, trophic food-webs The oceanic fine scales are highly energetic features (eddies, fronts, meanders, filaments) with relatively short lifetimes (days/weeks to months). Due to their associated strong gradients in physical and biogeochemical properties, they crucially affect ocean physics and ecology with potential impacts at the climate scale. The temporal scale associated with these horizontal and vertical fine scales is the same as many important ecological processes including phytoplankton growth and competition. This temporal resonance is one of the reasons behind the fine-scale variability appearing in the marine ecosystems structure and related domains, including biogeochemical cycles, trophic food-webs up to resources and biodiversity.Over the past few decades, great progresses have been made in characterizing fine scales through modeling. Remote sensing is also improving rapidly in terms of resolution, with landmark missions like SWOT expected to be operational very soon (2022). However, in situ sampling remains challenging due to the difficulties of mapping a large domain covering the length of a filament or the diameter of an eddy (~100km) at high spatio-temporal frequency (~km and ~daily).Here we present some sampling strategies we are developing for addressing this issue by combining remote sensing and in situ multi-platform high-resolution sampling of physical, biogeochemical and biological variables. In a series of campaigns in the Mediterranean Sea (OSCAHR 2015, PROTEVSMED-SWOT 2018, FUMSECK 2019), satellite-based adaptive and Lagrangian strategies proved to be successful to target and follow fine scale structures in situ. When paired with in situ biological measurements, like automated cytometry, these strategies highlight the important role of the fine scales in structuring the phytoplankton community by acting as fluid dynamical barriers and biodiversity hot-spots.To extend these observations to other regions, we support an international coordinated experimental effort of the fine scale community at several sites all around the world to fully exploit the great opportunities offered by the launch of the satellite SWOT.
Published: 2020
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71. Mapping Nature-based Marine Flooding Risk using VHR Wave, Airborne LiDAR and Satellite Imagery: The Case Study of the Dol Marsh (Bay of Mont-Saint-Michel, France)

Author: Dorothée James, Antoine Mury, Matthieu Jeanson, Antoine Collin, Samuel Etienne, Hélène Gloria, Yves Pastol, École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL), Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN), Littoral, Environnement, Télédétection, Géomatique (LETG - Dinard), Université de Nantes (UN)-Université de Nantes (UN)-Université de Caen Normandie (UNICAEN), Centre Universitaire de Formation et de Recherche de Mayotte (CUFR), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Cognitions Humaine et ARTificielle (CHART), Université Paris 8 Vincennes-Saint-Denis (UP8)-École pratique des hautes études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Nanterre (UPN)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)
Subjects: spatial modelling, 010504 meteorology & atmospheric sciences, flooding risk, [SDE.MCG]Environmental Sciences/Global Changes, [INFO.INFO-NE]Computer Science [cs]/Neural and Evolutionary Computing [cs.NE], 01 natural sciences, Ecosystem services, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, [STAT.ML]Statistics [stat]/Machine Learning [stat.ML], [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, [SPI.GCIV.RISQ]Engineering Sciences [physics]/Civil Engineering/Risques, Satellite imagery, Wave, 14. Life underwater, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Risk management, attenuation, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Vulnerability (computing), Remote sensing, [SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph], Adaptive capacity, Ecology, 010505 oceanography, business.industry, [SDE.IE]Environmental Sciences/Environmental Engineering, Flooding (psychology), [SHS.GEO]Humanities and Social Sciences/Geography, risk exposure, [SDE.ES]Environmental Sciences/Environmental and Society, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Lidar, 13. Climate action, Breakwater, [INFO.INFO-TI]Computer Science [cs]/Image Processing [eess.IV], [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, [INFO.INFO-BI]Computer Science [cs]/Bioinformatics [q-bio.QM], business, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, [STAT.ME]Statistics [stat]/Methodology [stat.ME]
Abstract: International audience; A growing interest in nature-based solutions has gained unprecedented attention in the coastal risk management, to complement or replace conventional approaches like hard structures (dykes, seawalls, breakwaters). However, due to the diversity of coastal ecosystems and the heterogeneity of the ecosystem service of wave attenuation they can induce, the integration of their protective role in an accurate way into risk studies remains rare. This paper shows an experimental methodology to integrate this ecosystem service into the risk mapping at very high spatial resolution using in situ sensors, airborne LiDAR and spaceborne satellite imagery. Risk study is achieved using a combination of indices which allows to evaluate the asset's exposure and vulnerability. The nature-based solution is also integrated through the creation of an adaptive capacity index, based on a spatially-explicit model of wave attenuation. The study enables to highlight the assets which are the most concerned by the marine flooding risk, using a synthetic risk index ranging from 0 to 1.
Published: 2020
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72. Ecological model of the Bay of Biscay and English Channel shelf for environmental status assessment part 1: Nutrients, phytoplankton and oxygen

Author: Fabrice Lecornu, Franck Dumas, Morgan Dussauze, Valerie Garnier, Michel Repecaud, Benedicte Thouvenin, Alain Menesguen, Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Laboratoire d'Océanographie Physique et Spatiale (LOPS), and Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Atmospheric Science, Ecological 3D model, 010504 meteorology & atmospheric sciences, Temperature salinity diagrams, Oceanography, 01 natural sciences, Dissolved oxygen, Phytoplankton, Computer Science (miscellaneous), 14. Life underwater, MSFD, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Buoy, 010505 oceanography, Continental shelf, Abyssal plain, Bay of Biscay and English Channel, Geotechnical Engineering and Engineering Geology, Surface chlorophyll, Water Framework Directive, [SDU]Sciences of the Universe [physics], 13. Climate action, Environmental science, Eutrophication, Bay
Abstract: International audience; European directives (Water Framework Directive - WFD and Marine Strategy Framework Directive - MSFD) require a regular survey of several descriptors of the Environmental Status of coastal waters of the North-east Atlantic Ocean. Especially for the MSFD, which may concern large continental shelf areas where measurements are scarce, realistic ecological models can help assessing the Environmental Status. The ECO-MARS3D model of the pelagic ecosystem of the Bay of Biscay and English Channel continental shelf (NE Atlantic) has been developed for these applied purposes and validated against various types of historic data. This first paper deals with the basic biogeochemical version, which contains inorganic nutrients (NH4, NO3, PO4, Si(OH)4), three phytoplankton bulk types (diatoms, nanoflagellates and dinoflagellates), two zooplankton bulk types, particulate detrital forms and dissolved oxygen. A second paper presents a version of this model including 3 harmful phytoplanktonic groups. A simulation covering the 2000-2010 decade is compared to satellite sea surface data for temperature and surface chlorophyll, to the Southampton-Bilbao and Ouistreham-Portsmouth ferrybox surface data for temperature, salinity, chlorophyll and nutrients, to point samples provided by the French network of phytoplankton monitoring (REPHY) for inorganic nutrients and chlorophyll, and to high frequency time series of dissolved oxygen measured by a moored automatic buoy. From a spatial point of view, the model provides realistic fields of annual means of surface temperature (but with a systematic bias of about + 1.0 °C) and phytoplanktonic biomass. From a seasonal point of view, the temperature and salinity follow correctly the observed variations. For nutrient and total chlorophyll, the model succeeds in reproducing the difference amounting to one order of magnitude between the North Sea coastal zones and the oligotrophic oceanic zone above the abyssal plain of the bay of Biscay. It also reproduces the spring-neap tide oscillation visible in satellite observations of surface chlorophyll. Simulated seasonal cycles are realistic in the coastal stations, but the French Atlantic coast seems slightly too nutrient-rich. In coastal eutrophicated areas, the model does not produce chlorophyll peaks as high as measured. In the Vilaine bay (France), the summer hypoxic conditions (down to 4 mg/L O2 or less) are correctly reproduced. This ecological model has been used off-line to map some classical eutrophication descriptors (winter DIN and DIP, March-October 90th percentile of chlorophyll) used by the WFD and MSFD European directives. It has also been turned into an operational real-time mode, as part of the French Previmer project (now: http://marc.ifremer.fr/resultats/production_primaire).
Published: 2019
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73. Evaluation of Atmospheric Correction Algorithms for Sentinel-2-MSI and Sentinel-3-OLCI in Highly Turbid Estuarine Waters

Author: Renosh, Pannimpullath Remanan, Doxaran, David, Keukelaere, Liesbeth De, Gossn, Juan Ignacio, Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Flemish Institute for Technological Research (VITO), Instituto de Astronomía y Física del Espacio [Buenos Aires] (IAFE), and Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Universidad de Buenos Aires [Buenos Aires] (UBA)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Sentinel-3-OLCI, [SDE.IE]Environmental Sciences/Environmental Engineering, SENTINEL-2-MSI, Science, Sentinel-2-MSI, SUSPENDED PARTICULATE MATTER, suspended particulate matter, SENTINEL-3-OLCI, purl.org/becyt/ford/1 [https], purl.org/becyt/ford/1.5 [https], highly turbid waters, ocean color remote sensing, OCEAN COLOR REMOTE SENSING, LANDSAT-8/OLI, atmospheric correction, ATMOSPHERIC CORRECTION, Landsat-8-OLI, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, HIGHLY TURBID WATERS
Abstract: The present study assesses the performance of state-of-the-art atmospheric correction (AC) algorithms applied to Sentinel-2-MultiSpectral Instrument (S2-MSI) and Sentinel-3-Ocean and Land Color Instrument (S3-OLCI) data recorded over moderately to highly turbid estuarine waters, considering the Gironde Estuary (SW France) as a test site. Three spectral bands of water-leaving reflectance (Rhow) are considered: green (560 nm), red (655 or 665 nm) and near infrared (NIR) (865 nm), required to retrieve the suspended particulate matter (SPM) concentrations in clear to highly turbid waters (SPM ranging from 1 to 2000 mg/L). A previous study satisfactorily validated Acolite short wave infrared (SWIR) AC algorithm for Landsat-8-Operational Land Imager (L8-OLI) in turbid estuarine waters. The latest version of Acolite Dark Spectrum Fitting (DSF) is tested here and shows very good agreement with Acolite SWIR for OLI data. L8-OLI satellite data corrected for atmospheric effects using Acolite DSF are then used as a reference to assess the validity of atmospheric corrections applied to other satellite data recorded over the same test site with a minimum time difference. Acolite DSF and iCOR (image correction for atmospheric effects) are identified as the best performing AC algorithms among the tested AC algorithms (Acolite DSF, iCOR, Polymer and C2RCC (case 2 regional coast color)) for S2-MSI. Then, the validity of six different AC algorithms (OLCI Baseline Atmospheric Correction (BAC), iCOR, Polymer, Baseline residual (BLR), C2RCC-V1 and C2RCC-V2) applied to OLCI satellite data is assessed based on comparisons with OLI and/or MSI Acolite DSF products recorded on a same day with a minimum time lag. Results show that all the AC algorithms tend to underestimate Rhow in green, red and NIR bands except iCOR in green and red bands. The iCOR provides minimum differences in green (slope = 1.0 ± 0.15, BIAS = 1.9 ± 4.5% and mean absolute percentage error (MAPE) = 12 ± 5%) and red (slope = 1.0 ± 0.17, BIAS = −9.8 ± 9% and MAPE = 28 ± 20%) bands with Acolite DSF products from OLI and MSI data. For the NIR band, BAC provides minimum differences (slope = 0.7 ± 0.13, BIAS = −33 ± 17% and MAPE = 55 ± 20%) with Acolite DSF products from OLI and MSI data. These results based on comparisons between almost simultaneous satellite products are supported by match-ups between satellite-derived and field-measured SPM concentrations provided by automated turbidity stations. Further validation of satellite products based on rigorous match-ups with in-situ Rhow measurements is still required in highly turbid waters. Fil: Renosh, Pannimpullath Remanan. Sorbonne University; Francia. Centre National de la Recherche Scientifique; Francia Fil: Doxaran, David. Sorbonne University; Francia. Centre National de la Recherche Scientifique; Francia Fil: Keukelaere, Liesbeth De. Flemish Institute For Technological Research; Bélgica Fil: Gossn, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina
Published: 2020
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74. Intensive use of Lagrangian trajectories to quantify coastal area dispersion

Author: Sebastien Petton, Stephane Pouvreau, Franck Dumas, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Local diffusivity, 010504 meteorology & atmospheric sciences, 010505 oceanography, Mars Exploration Program, Forcing (mathematics), Oceanography, Thermal diffusivity, Atmospheric sciences, 01 natural sciences, Physics::Geophysics, 13. Climate action, Lagrangian analysis, Environmental science, Marine ecosystem, Hydrodynamic model, 14. Life underwater, Diffusion (business), [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Dispersion (water waves), Scale (map), Barycentric repositioning method, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences
Abstract: WOS:000510365700001; International audience; Coastal waters are subject to great environmental and anthropogenic pressures. The diffusion and the transport of these waters are a key element for environmental, ecological and economic management. There are numerous indicators of hydrological characteristics based on theories of transport time scale. However, these indicators strongly depend on the geographical shape of the studied area and tend to give information after long integration time periods, generally on the order of weeks. Here, to qualify a coastal area's dispersion more precisely, we combined two Lagrangian approaches and estimated a local diffusivity. This paper presents the numerical implementation and the results obtained over a tidally flushed, semi-enclosed water body located at mid-latitude. This new coefficient was estimated using the hydrodynamic model MARS 3D with a barycentric repositioning technique over a tidal period to ensure its reliability. We highlight the existing relationships between local diffusivity and both horizontal and vertical processes. Methodological aspects were analysed based on a reference case (number and distribution of particles, resolution, integration time period). The consistency and sensitivity of the coefficient were studied with different forcing conditions (hydrodynamical and meteorological regimes). In conclusion, our local diffusivity provides a new perspective for understanding the land-sea interface and coastal dispersion and holds potential for future studies of coastal marine ecosystems.
Published: 2020
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75. A Lagrangian strategy for in situ sampling the physical-biological coupling at fine scale : the PROTEVSMED-SWOT 2018 cruise

Author: Gérald Grégori, Ananda Pascual, Franck Dumas, Stéphanie Barrillon, Francesco d'Ovidio, Andrea Doglioli, Lloyd Izard, Roxane Tzortzis, Melilotus Thyssen, Anne Petrenko, Frédéric Cyr, Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Processus et interactions de fine échelle océanique (PROTEO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut Mediterrani d'Estudis Avancats (IMEDEA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Universidad de las Islas Baleares (UIB), Northwest Atlantic Fisheries Centre (NWAFC), Fisheries and Oceans Canada (DFO), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Water mass, Mediterranean sea, Diurnal cycle, Climatology, Phytoplankton, Front (oceanography), Sampling (statistics), Environmental science, Satellite, 14. Life underwater, Sea-surface height
Abstract: The term "fine scales" is generally used to refer to the ocean processes occuring on horizontal scales smaller than 10 km andcharacterized by a short lifetime (days/weeks). Fine scales have been predominantly studied with numerical simulations andsatellite observations which have highlighted their significant role on biological processes. Indeed, their short time scale is thesame as a lot of important processes in phytoplankton dynamics. Model simulations have shown that fine scales such as frontsand filaments strongly influence the distribution of phytoplankton species. Nowadays, the combination of in situ measurements,satellite observations and model simulations is a necessity to better understand these mechanisms. However these processesare particularly challenging to sample in situ because of their size and their ephemeral nature. The PROTEVSMED-SWOT cruise was performed in the Western Mediterranean Sea, in the southern region of the BalearicIslands, onboard BHO Beautemps-Beaupré, between April 30 th and May 14 th , 2018. In order to study the influence of finescales on the distribution of phytoplankton species, a satellite-based adaptive Lagrangian sampling strategy has been deployedin order to i) identify a fine scale structure of interest, ii) sample it at high spatial resolution the phytoplankton community, andiii) follow the evolution of this structure and the related distribution of phytoplankton. The SPASSO software package usessatellite altimetry, SST and surface Chl a concentration data to generate and provide near-real time daily maps of the dynamicaland biogeochemical structures present in the area. The sampling strategy was defined in order to cross a frontal zone separatingdifferent types of water. Multidisciplinary in situ sensors (hull-mounted ADCP, a Seasoar towed fish and an automated flowcytometer installed on the seawater supply of the Thermosalinograph) were used to sample at high spatial resolution physicaland biological variables. A particular attention was put in adapting the temporal sampling in different water masses to thebiological time scales in order to reconstruct the phytoplankton diurnal cycle. Such a strategy was successful in sampling two different water masses separated by a narrow front and characterized bydifferent aboundances of several phytoplankton species and functional groups. Consequently, our results highlight the role ofthe front on the physical and biological coupling confirming previous modelling and remote-sensing studies. The new generation of altimetric satellite, SWOT, will provide a 2D sea surface height at an unprecedented resolution andit will be a unique opportunity to better observe fine scale structures in the global ocean. Our methodology paves the way tofuture in situ experiments that are planned in 2022 during the SWOT fast-sampling phase, few months after its launch.
Published: 2020
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76. TVD IMEX Runge-Kutta schemes based on arbitrarily high order Butcher tableaux

Author: Michel-Dansac, Victor, Thomann, Andrea, Institut de Mathématiques de Toulouse UMR5219 (IMT), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Scienze e Alta Tecnologia, Università degli Studi dell’Insubria, Service Hydrographique et Océanographique de la Marine (SHOM), and INDAM-DP-COFUND-2015, grant number 713485
Subjects: L∞ stability, MOOD, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], IMEX RK schemes, hyperbolic multi-scale equations, Computer Science::Numerical Analysis, TVD, [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA], Mathematics::Numerical Analysis
Abstract: The context of this work is the development of TVD Implicit-Explicit Runge-Kutta schemes to approximate the solution of hyperbolic multi-scale equations. A key feature of IMEX-RK schemes is that the resulting CFL condition does not depend on the stiff part of the considered equation, as long as this stiff part is treated implicitly. However, the negative result from Gottlieb et al. states that it is not possible to construct an implicit Runge-Kutta scheme of order higher than one that is either L ∞ stable or TVD. We show that this result is also valid for IMEX-RK schemes. Therefore, rather than building a high-order TVD scheme, the goal of this work is to provide a way of improving the precision of a first-order IMEX-RK scheme, while retaining its L ∞ stability and TVD properties. To that end, we introduce a convex combination between an oscillatory high-order IMEX-RK scheme and the stable but diffusive first-order IMEX-RK scheme. We derive generic conditions to ensure the TVD property for a convex combination based on an arbitrarily high order Butcher tableau. To increase the precision, we combine our new TVD schemes with an optimal order detection strategy inspired by the MOOD framework. We compare them to L-stable methods from the literature, applied on a two-scale hyperbolic equation where we test the performance on continuous and discontinuous solutions.
Published: 2020

77. LES Modelling of the Impact of the Topography on Large-scale Exchange Flow in the Strait of Gibraltar

Author: Hilt, Margaux, Roblou, Laurent, Nguyen, Cyril, Marchesiello, Patrick, Lemarié, Florian, Jullien, Swen, DUMAS, Franck, Debreu, Laurent, Capet, Xavier, Bordois, Lucie, Benshila, Rachid, Auclair, Francis, Laboratoire d'aérologie (LAERO), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Mathematics and computing applied to oceanic and atmospheric flows (AIRSEA), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Grenoble Alpes (UGA)-Laboratoire Jean Kuntzmann (LJK), Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Processus et interactions de fine échelle océanique (PROTEO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Hilt, Margaux, Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2020

78. Numerical modelling of three-dimensional wave-current interactions in complex environment : application to Alderney Race

Author: Franck Dumas, Jean-François Filipot, Pascal Bailly du Bois, Lucille Furgerot, Cyril Lathuilière, Tina Odaka, Anne-Claire Bennis, Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Universitaire des Sciences Appliquées de Cherbourg (LUSAC), Normandie Université (NU)-Normandie Université (NU), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), France Energies Marines [Brest], and Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Stokes drift, [PHYS.PHYS.PHYS-FLU-DYN]Physics [physics]/Physics [physics]/Fluid Dynamics [physics.flu-dyn], Turbulent mixing, Friction reducing, Breaking wave, 020101 civil engineering, Ocean Engineering, 02 engineering and technology, Mechanics, 01 natural sciences, Tidal current, Physics::Geophysics, 010305 fluids & plasmas, 0201 civil engineering, Current (stream), symbols.namesake, Tidal cycle, 13. Climate action, 0103 physical sciences, [SDE]Environmental Sciences, symbols, Astrophysics::Earth and Planetary Astrophysics, 14. Life underwater, Dimensioning, Geology
Abstract: (IF 2.98; Q1); International audience; Modelling three-dimensional wave-current-turbulence interactions in extreme tidal environments is still challenging and necessary for the development of the tidal industry, particularly for the dimensioning of tidal converters. Following this objective, we focus our study on the Alderney Race (France) where the strongest tidal current in Western Europe and various sea states occur. Due to the strong tidal current at this location, wave-current interactions were poorly studied by the past. Therefore, we propose to assess the impacts of wave-current interactions in Alderney Race by the use of a 3D fully-coupled wave-current numerical model and in-situ measurements. The following wave-current interactions were observed : i) Stokes drift e ects inducing an increase/decrease in the current depending on the angle between waves and current, ii) wave enhancement of the bottom friction reducing the tidal current, iii) refraction of waves by the current, generating changes in waves directions, and iv) wave breaking ascribed to tidal current. The impact of such interactions were maximal near the reverse event ( 1h30) and for a weak/medium tidal range. A non-stationary time delay, varying within a same tidal cycle, was noted at both locations, which is reduced by including the local wind e ects and by adjusting the bottom stress formulation. This study shows that wave-current interactions play a non-negligible role in Alderney Race and that they need to consider by the tidal industry.
Published: 2020
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79. Ocean Color Remote Sensing of Suspended Sediments along a Continuum from Rivers to River Plumes: Concentration, Transport, Fluxes and Dynamics

Author: Anouck Ody, David Doxaran, Romaric Verney, François Bourrin, Guillaume P. Morin, Ivane Pairaud, Aurélien Gangloff, Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Dynamique Hydro-sédimentaire (DHYSED), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre de Formation et de Recherche sur les Environnements Méditérranéens (CEFREM), Université de Perpignan Via Domitia (UPVD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Risques, Ecosystèmes, Vulnérabilité, Environnement, Résilience (RECOVER), Aix Marseille Université (AMU)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, CNES-TOSCA (TTC project) French research program, EC2CO (DeltaRhone project) French research program, and ANR-14-ASTR-0021,MATUGLI,Mesures Autonomes de la Turbidité côtière à l'aide de GLIders(2014)
Subjects: ocean color, suspended particulate matter, river mouth continuum, liquid and solid river discharges into the coastal ocean, Transport, Fluxes and ocean color, General Earth and Planetary Sciences, ZABR, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract: International audience; This study investigates the capability of high and medium spatial resolution ocean color satellite data to monitor the transport of suspended particulate matter (SPM) along a continuum from river to river mouth to river plume. An existing switching algorithm combining the use of green, red and near-infrared satellite wavebands was improved to retrieve SPM concentrations over the very wide range (from 1 to more than 1000 g.m−3) encountered over such a continuum. The method was applied to time series of OLI, MSI, and MODIS satellite data. Satisfactory validation results were obtained even at the river gauging station. The river liquid discharge is not only related to the SPM concentration at the gauging station and at the river mouth, but also to the turbid plume area and SPM mass estimated within the surface of the plume. The overall results highlight the potential of combined field and ocean color satellite observations to monitor the transport and fluxes of SPM discharged by rivers into the coastal ocean.
Published: 2022
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80. Classification of Land-Water Continuum Habitats Using Exclusively Airborne Topobathymetric Lidar Green Waveforms and Infrared Intensity Point Clouds

Author: Mathilde Letard, Antoine Collin, Thomas Corpetti, Dimitri Lague, Yves Pastol, Anders Ekelund, Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Brest (UBO)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (Nantes Univ - IGARUN), Nantes Université - pôle Humanités, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Humanités, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Littoral, Environnement, Télédétection, Géomatique (LETG - Rennes ), Université de Brest (UBO)-Université de Rennes 2 (UR2)-Nantes Université (Nantes Univ)-Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (Nantes Univ - IGARUN), Nantes Université (Nantes Univ), Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, ARED, Région Bretagne, non applicable, Saur Group, Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (NantesUniv – IGARUN), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Observatoire des Sciences de l'Univers de Rennes (OSUR), and Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: full-waveform lidar, [SDE.IE]Environmental Sciences/Environmental Engineering, topobathymetric lidar, Science, habitat mapping, [SDE.ES]Environmental Sciences/Environmental and Society, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], classification, coastal habitats, General Earth and Planetary Sciences, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract: International audience; Coastal areas host highly valuable ecosystems that are increasingly exposed to the threats of global and local changes. Monitoring their evolution at a high temporal and spatial scale is therefore crucial and mostly possible through remote sensing. This article demonstrates the relevance of topobathymetric lidar data for coastal and estuarine habitat mapping by classifying bispectral data to produce 3D maps of 21 land and sea covers at very high resolution. Green lidar full waveforms are processed to retrieve tailored features corresponding to the signature of those habitats. These features, along with infrared intensities and elevations, are used as predictors for random forest classifications, and their respective contribution to the accuracy of the results is assessed. We find that green waveform features, infrared intensities, and elevations are complimentary and yield the best classification results when used in combination. With this configuration, a classification accuracy of 90.5% is achieved for the segmentation of our dual-wavelength lidar dataset. Eventually, we produce an original mapping of a coastal site under the form of a point cloud, paving the way for 3D classification and management of land and sea covers.; Coastal areas host highly valuable ecosystems that are increasingly exposed to the threats of global and local changes. Monitoring their evolution at a high temporal and spatial scale is therefore crucial and mostly possible through remote sensing. This article demonstrates the relevance of topobathymetric lidar data for coastal and estuarine habitat mapping by classifying bispectral data to produce 3D maps of 21 land and sea covers at very high resolution. Green lidar full waveforms are processed to retrieve tailored features corresponding to the signature of those habitats. These features, along with infrared intensities and elevations, are used as predictors for random forest classifications, and their respective contribution to the accuracy of the results is assessed. We find that green waveform features, infrared intensities, and elevations are complimentary and yield the best classification results when used in combination. With this configuration, a classification accuracy of 90.5% is achieved for the segmentation of our dual-wavelength lidar dataset. Eventually, we produce an original mapping of a coastal site under the form of a point cloud, paving the way for 3D classification and management of land and sea covers.
Published: 2022
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81. Semi-implicit staggered mesh scheme for the multi-layer shallow water system

Author: Arnaud Duran, Rémy Baraille, Jean-Paul Vila, Institut Camille Jordan [Villeurbanne] (ICJ), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet [Saint-Étienne] (UJM)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon, Modélisation mathématique, calcul scientifique (MMCS), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet [Saint-Étienne] (UJM)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA), Service Hydrographique et Océanographique de la Marine (SHOM), and Ministère de la Défense
Subjects: Scheme (programming language), energy dissipation, Mathematical optimization, multilayer shallow water, Advection, 010103 numerical & computational mathematics, General Medicine, staggered meshes, 01 natural sciences, non linear stability, Term (time), 010101 applied mathematics, Waves and shallow water, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], Applied mathematics, Polygon mesh, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], 0101 mathematics, Diffusion (business), computer, Multi layer, [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA], Mechanical energy, Mathematics, computer.programming_language
Abstract: International audience; We present a semi-implicit scheme for a two-dimensional multilayer shallow water system with density stratification, formulated on general staggered meshes. The main result of the present note concerns the control of the mechanical energy at the discrete level, principally based on advective fluxes implying a diffusion term expressed in terms of the gradient pressure. The scheme is also designed to capture the dynamics of low-Froude number regimes and offers interesting positivity and well-balancing results. A numerical test is proposed to highlight the scheme's efficiency in the one layer case.; Nous proposons un schéma semi-implicite destiné à un modèle shallow water multicouches 2d avec stratification en densité, formulé sur maillages décalés généraux. Le principal résultat de cette note concerne le contrôle de l'énergie mécanique au niveau discret, qui se base principalement sur des flux advectifs faisant intervenir un terme de diffusion exprimé en fonction du gradient de pression. Le schéma est aussi conçu pour capturer les dynamiques des régimes à faible nombre de Froude et offre d'intéressantes propriétés en termes de positivité et préservation des états d'équilibre. Un test numérique est proposé pour illustrer l'efficacité du schéma dans le cas monocouche.
Published: 2017
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82. Active tectonics of the Calabrian subduction revealed by new multi-beam bathymetric data and high-resolution seismic profiles in the Ionian Sea (Central Mediterranean)

Author: Benoît Loubrieu, Heidrun Kopp, Laurine San Pedro, César R. Ranero, Thierry Garlan, Stéphane Dominguez, Ingo Klaucke, Valentí Sallarès, Paul Wintersteller, Sebastian Krastel, Gerhard Bohrmann, Marc-André Gutscher, Yann Le Faou, Marzia Rovere, Sébastien Zaragosi, Bernard Mercier de Lépinay, European Commission, Domaines Océaniques (LDO), Centre National de la Recherche Scientifique (CNRS)-Institut d'écologie et environnement-Observatoire des Sciences de l'Univers-Université de Brest (UBO)-Institut national des sciences de l'Univers (INSU - CNRS), Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Christian-Albrechts-Universität zu Kiel (CAU), Center for Marine Environmental Sciences [Bremen] (MARUM), Universität Bremen, Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Ifremer - Pouzané, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS), Institute for marine sciences, Consiglio Nazionale delle Ricerche [Roma] (CNR), Géoazur (GEOAZUR 7329), Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Institució Catalana de Recerca i Estudis Avançats (ICREA), Unitat de Tecnologia Marina (UTM), Centre Mediterrani d'Investigacions Marines I ambientals, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), GEOMAR - Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Environnements et Paléoenvironnements OCéaniques (EPOC), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Géosciences Marines (GM), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)
Subjects: seismic profiles, Accretionary wedge, 010504 meteorology & atmospheric sciences, bathymetry, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Escarpment, Active fault, Fault (geology), 010502 geochemistry & geophysics, Clastic wedge, 01 natural sciences, Geochemistry and Petrology, Eurasia-Africa plate boundary, Earth and Planetary Sciences (miscellaneous), Active faults, 14. Life underwater, active faults, accretionary wedge, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Subduction, Seismic profiles, Seafloor spreading, Geophysics, Sinistral and dextral, Space and Planetary Science, Bathymetry, subduction, Geology, Seismology
Abstract: Gutscher, Marc-André ... et al.-- 12 pages, 14 figures, 2 appendices, The detailed morphology and internal structure of the Calabrian accretionary wedge and adjacent Eastern Sicily margin are imaged in unprecedented detail by a combined dataset of multi-beam bathymetry and high-resolution seismic profiles. The bathymetric data represent the results of 6 recent marine geophysical surveys since 2010 as well as a compilation of earlier surveys presented as a 2 arc-sec (60 m) grid. Several distinct morpho-tectonic provinces are identified including: the deeply incised Malta–Hyblean Escarpment, numerous submarine canyons, broad regions of relatively flat seafloor dominated by fields of sediment waves, the gently undulating anticlinal fold-and-thrust belts of the external Calabrian accretionary wedge and the adjacent portion of the Western Mediterranean Ridge. The Calabrian arc can be divided into 4 domains (from SE to NW): 1) the undeformed Ionian abyssal plain, 2) the external evaporitic wedge, 3) the internal clastic wedge, 4) the Calabrian backstop (Variscan crystalline basement). The Calabrian accretionary wedge can also be divided laterally into two major lobes, the NE- and the SW lobes, and two minor lobes. The kinematics of the limit between the two major lobes is investigated and shown to be sinistral in the external (evaporitic) wedge. A network of radial slip lines within the southernmost external wedge unequivocally demonstrate ongoing dextral displacement of a rigid indenter (representing the corner of the clastic wedge) into the evaporitic wedge thereby confirming the geodynamic model of an active lateral slab tear fault here off eastern Sicily. The slab tear produces a series of major sub-parallel dextral strike-slip faults offshore Mt. Etna and south of the Straits of Messina consistent with the relative motions between Calabria and the Peloritan domain (NE Sicily). Abundant strike-slip faulting, and wide-spread folding and thrusting observed throughout the entire accretionary wedge, indicate regional shortening between the Ionian abyssal plain (foreland) and the Calabrian–Peloritan backstop caused by active subduction, We acknowledge INSU for funding related to the CIRCEE cruise and the European Union 7th Framework project ASTARTE, grant #603839, on Tsunami Hazard in Europe for support to MAG
Published: 2017
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83. Optical Mapping, a Promising Alternative to Gold Standard Cytogenetic Approaches in Acute Lymphoblastic Leukemias: A Blind Comparison on 10 Patients

Author: Nicolas Duployez, Joyce S. Lee, Valentin Lestringant, Nathalie Grardel, Anne Lutun, Michaela West, Yann Ferret, Dominique Penther, Loïc Garçon, Jean-Pierre Marolleau, Claude Preudhomme, Université de Picardie Jules Verne (UPJV), Cancer Heterogeneity, Plasticity and Resistance to Therapies - UMR 9020 - U 1277 (CANTHER), Institut Pasteur de Lille, Réseau International des Instituts Pasteur (RIIP)-Réseau International des Instituts Pasteur (RIIP)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Lille-Centre Hospitalier Régional Universitaire [Lille] (CHRU Lille)-Centre National de la Recherche Scientifique (CNRS), Génomique et Médecine Personnalisée du Cancer et des Maladies Neuropsychiatriques (GPMCND), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut National de la Santé et de la Recherche Médicale (INSERM), CHU Lille, CHU Amiens-Picardie, Bionano Genomics Inc, HEMATIM - Hématopoïèse et immunologie - UR UPJV 4666 (HEMATIM), Université de Picardie Jules Verne (UPJV)-CHU Amiens-Picardie-Institut National de la Santé et de la Recherche Médicale (INSERM), Laboratoire d'Hématologie [CHU Amiens], Service Hydrographique et Océanographique de la Marine (SHOM), and Ministère de la Défense
Subjects: medicine.medical_specialty, [SDV]Life Sciences [q-bio], Immunology, Pseudoautosomal region, Cytogenetics, Locus (genetics), Chromosomal translocation, Karyotype, Cell Biology, Hematology, Computational biology, Biology, medicine.disease, Biochemistry, Gene mapping, medicine, Copy-number variation, Trisomy, ComputingMilieux_MISCELLANEOUS
Abstract: Acute lymphoblastic leukemias (ALL) are characterized by a large number of genetic abnormalities of prognostic and theranostic interest. Their detection requires the use of several conventional and molecular cytogenetic techniques in order to establish the most exhaustive genetic profile: conventional karyotype, FISH, SNP-Array and RT-MLPA for detection of fusion transcripts. Optical genome mapping technique is based on analysis of ultra-high molecular weight DNA (UHMW: 150 kbp-2.5 Mbp). It allows an automatic, high resolution, genome-wide detection of structural anomalies, including balanced translocations and copy number anomalies, making this technology a promising tool in ALL. However, very few data are available in ALL so far. Our objective was to compare optical mapping (Bionano Genomics) to standard techniques performed routinely (combination of karyotype, FISH, SNP-array and RT-MLPA) in 10 selected B or T-ALL patients carrying at least one major genetic abnormality including t(10;14) TLX1-TRA, t(9;22) BCR-ABL1 (e1a2 and e14a2 transcripts), t(10;11) MLLT10-PICALM, t(11;19) KMT2A-MLLT1, typical hyperdiploid profile, iAMP21, SET-NUP214 fusion, various deletions involving CDKN2A/CDKN2B, IKZF1, PAX5, PTEN, ERG and FBXW7. Abnormalities on SNP-array were retained when allele fraction was > 10% and larger than 1Mbp or > 20 kbp and involving one of the 186 genes defined as potentially relevant in leukemogenesis. A total of 79 anomalies meeting these criteria in SNP-array, and/or found by other standard techniques were identified (45 deletions, 16 whole chromosome gains, 10 duplications or partial gains, and 8 translocations). Bone marrow DMSO pellets from the 10 patients, all treated at the CHU Amiens-Picardie, were used for this study. The UHMW DNA extraction technique provided molecules with an average N50 (≥ 150 kbp) of 286 kbp, and an average coverage of 339x. Direct imaging of the DNA molecules was performed on the Bionano Saphyr system and structural variants were automatically detected using the Rare Variant Pipeline. Abnormalities analysis was blindly performed by two independent operators on the Bionano Access software (v 1.5.2.), one cytogeneticist with no training in optical mapping (operator 1) and the other optical mapping technician without training in cytogenetics (operator 2). Among the 79 relevant anomalies, 72 (91.1%) were found by operator 1 and 71 (89.9%) by operator 2. All (8/8) translocations, 43/45 (95.6%) of deletions, 8/10 (80%) of gains were found by both operators whereas 13/16 (81.25%) and 12/16 (75%) of chromosomal gains were found by operator 1 and 2 respectively. Concerning the 8 discrepancies between optical mapping and standard techniques, 4 of them were filtering issues. Three were low allelic frequency large gains clearly visible in raw data but rejected by software's CNV filters, totally, or partially for a trisomy 3 that caused the discrepancy between the two observers. The fourth was a deletion of VPREB1 gene, erroneously eliminated by operators because included in recurrent deletion zones of IGL locus. The 4 others discrepancies were non detected anomalies. Two of them were copy number variations in Xp22.33 (pseudoautosomal region), a non-covered area with the optical mapping technology, one of which was a P2RY8-CRLF2 fusion. Another sub-clonal gain (trisomy 21) found by karyotype and FISH (quantified at 7% of all nuclei) but not by SNP-array, was missed, even in raw data. The last was a near-tetraploid subclone, found only on karyotype, that might be strictly tetraploid and by definition undetectable by quantitative techniques. Interestingly, new anomalies, not detected by standard techniques, were revealed, including a translocation t(11;14)(p13;q11.2) LMO2-TRA, a translocation with inversion t(7;8)(q34;q24.1) TRB-MYC and a translocation t(14;20)(q32.33;q13.13) IGH-CEBPB. At last, in 3 cases, unidentified complex rearrangements by cytogenetics could be resolved using optical mapping. Thus, optical mapping represents an innovative, time and cost effective alternative to the different cytogenetic techniques currently performed routinely for ALL genetic characterization. It enables identification of complex cytogenetic events, including those currently inaccessible to standard techniques such as chromotripsis or certain complex translocations. Disclosures Lee: Bionano Genomics, San Diego: Current Employment. Ferret:Bionano Genomics: Research Funding.
Published: 2020
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84. Bacterial Communities characterization in coastal sedimentary infilling under fluids seeps influence using metagenomics (Concarneau and Croisic bays)

Author: Murat, Anne, Poirier, Isabelle, Gregoire, Gwendoline, Moletta-Denat, Marina, Baltzer, Agnès, Champilou, Jean-Baptiste, Elodie, Marshes, Guyomard, Patrick, Ehrhold, Axel, Laboratoire Universitaire des Sciences Appliquées de Cherbourg (LUSAC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU), Laboratoire Géodynamique et enregistrement Sédimentaire - Geosciences Marines (GM-LGS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN), Laboratoire de Planétologie et Géodynamique - Angers (LPG-ANGERS), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, and Institut français de recherche pour l'exploitation de la mer (IFREMER)
Subjects: [SDE]Environmental Sciences, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2020

85. Assessing the Influence of Changes in Shoreface Morphology since the 19th Century on Nearshore Hydrodynamics and Shoreline Evolution in Northern France: A Modeling Approach

Author: Nicolas Pouvreau, Alexa Latapy, Arnaud Héquette, Amandine Nicolle, Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne), Département STIC [Brest] (STIC), Service Hydrographique et Océanographique de la Marine (SHOM), and Ministère de la Défense
Subjects: Shore, geography, geography.geographical_feature_category, Ecology, Sediment, Northern France, Current (stream), Oceanography, Sand banks, Calais, 13. Climate action, Erosion, Bathymetry, 14. Life underwater, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Progradation, Hydrodynamic circulation, Hydrography, Residual tidal currents, Geology, Seabed, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Earth-Surface Processes, Water Science and Technology
Abstract: Latapy A.; Hequette A.; Nicolle A., and Pouvreau N., 2020. Assessing the influence of changes in shoreface morphology since the 19th century on nearshore hydrodynamics and shoreline evolution in northern France: A modeling approach In: Malvarez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 542–547. Coconut Creek (Florida), ISSN 0749-0208.The shoreface off the coast of northern France is characterized by the presence of numerous tidal sand banks, forming linear shore-parallel or slightly oblique massive sand bodies. Digitization of historic hydrographic field sheets from the French Hydrographic Service (Shom) archives enabled to produce Digital Elevation Models (DEMs) of the seabed morphology at different dates since the early 19th century. Our analyses of bathymetry changes based on differential DEMs showed significant morphological variations across the shoreface near Calais during the 19th and 20th centuries, which are largely due to changes in nearshore sand bank morphology and position. Sand bank mobility can be partially explained by tidal current asymmetry, inducing an elongation and an alongshore migration of this sand body in the direction of the net residual tidal current. Observed changes in shoreface and nearshore morphology attempt to be related with possible variations in hydrodynamics, this paper presenting the results obtained on tidal currents. TELEMAC-2D model was used to simulate 2D velocity field and water depth during a spring and neap tidal cycle over bathymetry grids based on historical bathymetric soundings. Depending on the bathymetric setting, modeling of tidal residual currents revealed notable increases or decreases in residual current velocity during distinct time periods, particularly in nearshore areas, which may lead to seabed erosion where current strengthening is observed through time or conversely to sediment accumulation in areas of decreasing current velocity. These results are consistent with the shoreline changes that occurred during the 20th century, with a correspondence between nearshore areas of decreasing (or increasing) residual current velocity and adjacent shorelines that were affected by seaward progradation (or erosion), suggesting strong links between changes in seabed morphology over the shoreface and shoreline evolution.
Published: 2020
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86. Influence of shoreface morphological changes since the 19th century on nearshore hydrodynamics and shoreline evolution in Wissant Bay (northern France)

Author: Arnaud Héquette, Amandine Nicolle, Alexa Latapy, Nicolas Pouvreau, Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne), Département STIC [Brest] (STIC), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), and Université du Littoral Côte d'Opale (ULCO)
Subjects: 010504 meteorology & atmospheric sciences, Intertidal zone, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Wissant Bay, Sand banks, Geochemistry and Petrology, Wave height, Bathymetry, 14. Life underwater, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Seabed, Tidal currents, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Shore, geography, geography.geographical_feature_category, Geology, Hydrodynamic, TELEMAC, 13. Climate action, Waves, North Sea, France, Bay, Channel (geography)
Abstract: International audience; Located at the southern approaches to the North Sea, the Wissant Bay has had the most rapidly eroding shoreline in mainland France in recent decades. Using historical bathymetries spanning the second half of the 19th century to the present, an analysis of the long-term coastal morphological changes and evolution of a prominent sand bank (Line bank), extending across the bay, was carried out. A period of overall seabed erosion with a width-reduction of the Line bank; a deepening of the channel between the Line bank and the coast; and a lowering of the foreshore have been ongoing since the middle of the 20th century. This phase followed a period of channel infill in the western part of Wissant Bay in the early 20th century. Numerical modelling of wave propagation and tidal circulation was performed using the TELEMAC suite of models to get some insights into the influence of these bathymetry changes on coastal hydrodynamics. Two seabed configurations were identified revealing a contrasting hydrodynamic circulation. An erosional one induces an acceleration of tidal currents and an increase in wave height. Conversely, accumulation leads to an hydrodynamic regime weakening with a decrease in current velocity and to more wave energy dissipation in the nearshore. This study highlights the role of morphological feedbacks between nearshore morphology and coastal hydrodynamics. The identification of these feedbacks mechanisms at a historical time scale is important to assess potential drivers of coastal changes.
Published: 2020
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87. Cyclostrophic Corrections of AVISO/DUACS Surface Velocities and Its Application to Mesoscale Eddies in the Mediterranean Sea

Author: Artemis Ioannou, Briac LeVu, Franck Dumas, Alexandre Tuel, Alexandre Stegner, Sabrina Speich, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), MATERIAUX (MATERIAUX), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Centre d'Enseignement et de Recherche Eau Ville Environnement (CEREVE), AgroParisTech-École des Ponts ParisTech (ENPC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), DYNECO (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), and Dynamiques de l'Environnement Côtier (DYNECO)
Subjects: Surface (mathematics), [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010504 meteorology & atmospheric sciences, 010505 oceanography, Oceanography, 01 natural sciences, Mesoscale eddies, Geophysics, Mediterranean sea, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), 14. Life underwater, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: International audience
Published: 2019
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88. The influence of geomorphic setting on the frequency distribution of energy delivered to steep coastal cliffs from environmental forcings

Author: Woo, Han Byul, Dodet, Guillaume, Adams, Peter N., Earlie, Claire, Le Dantec, Nicolas, Leckler, Fabien, Perrot, Julie, Suanez, Serge, Augereau, Emmanuel, Ardhuin, Fabrice, University of Florida [Gainesville] (UF), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Cardiff University, Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet HA (Cerema Equipe-projet HA), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Littoral, Environnement, Télédétection, Géomatique (LETG - Brest), Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN)-Université de Caen Normandie (UNICAEN), Université de Nantes (UN)-Université de Nantes (UN), and Suanez, Serge
Subjects: [SDE] Environmental Sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.STU.GM] Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, [SDE]Environmental Sciences, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2019

89. Seismo-acoustic wave propagation in the Rade of Hyeres (France) generated by counter-mining of explosive devices: comparison between numerical simulations and real experiments

Author: Olivier Morio, Davis Ambrois, Thierry Garlan, Fang Wang, Anne Deschamps, Eric Beucler, Xavier Demoulin, Nathalie Favretto-Cristini, Paul Cristini, Ondes et Imagerie (O&I), Laboratoire de Mécanique et d'Acoustique [Marseille] (LMA ), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, MAREE, Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), and Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Seismometer, Acoustics and Ultrasonics, 010504 meteorology & atmospheric sciences, Explosive material, Computer simulation, Wave propagation, Detonation, 010502 geochemistry & geophysics, 01 natural sciences, [PHYS.MECA.ACOU]Physics [physics]/Mechanics [physics]/Acoustics [physics.class-ph], 03 medical and health sciences, 0302 clinical medicine, Acoustic wave propagation, Arts and Humanities (miscellaneous), 13. Climate action, 0103 physical sciences, 14. Life underwater, Underwater, 030223 otorhinolaryngology, 010301 acoustics, Seismology, Geology, Seabed, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: A series of underwater explosions detonations was conducted in December 2018 in the Rade of Hyeres in France. From topographical and sedimentary measurements performed in this area, physical and geometrical characteristics of the marine seabed have been carefully selected to serve as input data for numerical simulations of seismo-acoustic wave propagation, from the source to several seismometers deployed on the coast of Hyeres and surrounding islands. The numerical simulation is conducted using a spectral-element method. The source time function is estimated from in situ acoustic signals recorded by hydrophones located around the detonation location. The seismic data recorded on the coast are used to calibrate the numerical simulation and to evaluate the impact of different marine environments.
Published: 2019

90. Caractéristiques des signaux d'explosions de contre-minage en mer, enregistrés sur les côtes et aux stations permanentes Résif

Author: Beucler, Éric, Bonnin, Mickaël, Deschamps, Anne, Garlan, Thierry, Cristini, Nathalie, Wang, Fang, Mercerat, Diego, Cristini, Paul, Martin, Xavier, Ambrois, David, Mathias, Xavier, Brenon, Émeric, Morio, Olivier, Stéphan, Yann, Pernoud, Michel, Langlaude, Philippe, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Laboratoire de Mécanique et d'Acoustique [Marseille] (LMA ), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Direction Méditerranée (Cerema Direction Méditerranée), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Résif, and Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Sismologie, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], RESIF, France
Abstract: National audience; Le projet POSA a pour but de décrire et quantifier l'énergie sismique se propageant sur les côtes lors des explosions de contre-minage menées par la Marine. En 2018, un déploiement de capteurs proches des côtes a permis d'enregistrer les champs d'ondes sur une large gamme de fréquences. Le signal lié aux explosions se caractérise par deux phases d'énergie (ondes de compression dans le milieu solide et dans l'eau). L'efficacité de la conversion eau/roche dépend fortement de la topographie et de la nature de la côte. Les stations Résif permanentes n'enregistrent que la partie basse-fréquence de ce signal.
Published: 2019

91. Characteristics of counter-mining explosion signals at sea, recorded on coasts and at permanent RESIF stations

Author: É., Beucler, Bonnin, Mickael, Deschamps, Anne, Garlan, Thierry, Cristini, Nathalie, Wang, Fang, Mercerat, Diego, CRISTINI, Paul, MARTIN, Xavier, AMBROIS, David, mathias, xavier, Brenon, Emeric, Morio, Olivier, STHEPHAN, Yann, Pernoud, Michel, Langlaude, Philippe, Observatoire des Sciences de l'Univers Nantes Atlantique (OSUNA), Université d'Angers (UA)-Université de Nantes (UN)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université Gustave Eiffel (UNIV GUSTAVE EIFFEL), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Laboratoire de Mécanique et d'Acoustique [Marseille] (LMA ), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet MOUVGS (Cerema Equipe-projet MOUVGS), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA), Observatoire des Sciences de l'Univers Nantes Atlantiques (OSUNA), Université d'Angers (UA)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Conservatoire National des Arts et Métiers [CNAM] (CNAM), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université Gustave Eiffel, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Université d'Angers (UA)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM), and Bertrand, Véronique
Subjects: Sismologie, OCEAN, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], MER, RESIF, [SDU.STU.GP] Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], RLBP, Réseau sismologique, Seismology, Seismological network
Abstract: This poster presents the POSA project (Characterization of the Propagation of Seismic Waves of Anthropic Origin, ANR ASTRID 2015-2019), which aims to describe and quantify the seismic energy propagating on the coasts during counter-mining explosions carried out by the Navy. In 2018, a deployment of sensors close to the coasts made it possible to record the wave fields over a wide range of frequencies. The signal related to the explosions is characterized by two energy phases (compressional waves in the solid medium and in the water). The efficiency of the water/rock conversion is highly dependent on the topography and nature of the coast. Permanent RESIF stations record only the low-frequency part of this signal. This poster was presented during the RESIF Scientific and Technical Meetings that took place in Biarritz in November 2019. RESIF is a national research infrastructure dedicated to the observation and understanding of the Earth's internal structure and dynamics. RESIF is based on high technology observation networks, composed of seismological, geodetic and gravimetric instruments deployed in a dense manner throughout the French territory. The data collected allow the study with high spatio-temporal resolution of ground deformation, surface and deep structures, local and global seismicity and natural hazards, particularly seismic, on the French territory. RESIF is integrated into the European (EPOS - European Plate Observing System) and worldwide instruments that allow to image the Earth's interior in its entirety and to study numerous natural phenomena.; Ce poster présente le projet POSA (Caractérisation de la Propagation des Ondes Sismiques d’origine Anthropique, ANR ASTRID 2015-2019), qui a pour but de décrire et quantifier l'énergie sismique se propageant sur les côtes lors des explosions de contre-minage menées par la Marine. En 2018, un déploiement de capteurs proches des côtes a permis d'enregistrer les champs d'ondes sur une large gamme de fréquences. Le signal lié aux explosions se caractérise par deux phases d'énergie (ondes de compression dans le milieu solide et dans l'eau). L'efficacité de la conversion eau/roche dépend fortement de la topographie et de la nature de la côte. Les stations RESIF permanentes n'enregistrent que la partie basse-fréquence de ce signal. Ce poster a été présenté lors des Rencontres scientifiques et techniques RESIF qui se sont déroulées à Biarritz en novembre 2019. RESIF est une infrastructure de recherche nationale dédiée à l’observation et la compréhension de la structure et de la dynamique Terre interne. RESIF se base sur des réseaux d’observation de haut niveau technologique, composés d’instruments sismologiques, géodésiques et gravimétriques déployés de manière dense sur tout le territoire français. Les données recueillies permettent d’étudier avec une haute résolution spatio-temporelle la déformation du sol, les structures superficielles et profondes, la sismicité à l’échelle locale et globale et les aléas naturels, et plus particulièrement sismiques, sur le territoire français. RESIF s’intègre aux dispositifs européens (EPOS - European Plate Observing System) et mondiaux d’instruments permettant d’imager l’intérieur de la Terre dans sa globalité et d’étudier de nombreux phénomènes naturels.
Published: 2019

92. Uncertainties associated with in situ high-frequency long-term observations of suspended particulate matter concentration using optical and acoustic sensors

Author: Matthias Baeye, Marion Chapalain, Bouchra Nechad, Michael Fettweis, Aldo Sottolichio, Steffen Grünler, Jan Claus, Wim Vanhaverbeke, Janine J. Nauw, Frédéric Jourdin, Julien Deloffre, Flavie Druine, Styn Claeys, Marius Becker, Joan Backers, Tom Van Engeland, Hans Vereecken, Robert Lafite, Romaric Verney, Rüdiger Röttgers, T. Cox, Rolf Riethmüller, Davy Depreiter, Götz Flöser, Laboratoire de physique hydrodynamique et sédimentaire (DYNECO/PHYSED), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Division of Craniofacial Medicine, University of Washington [Seattle], Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), GéoHydrosystèmes COntinentaux (GéHCO EA6293), Université de Tours, Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Institut Royal des Sciences Naturelles de Belgique (IRSNB), Centre for Materials and Coastal Research [Geesthacht], Helmholtz-Zentrum Geesthacht (GKSS), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), and Université de Tours (UT)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Measurement uncertainty, Aquatic Science, 01 natural sciences, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, Temporal scales, Biology, 0105 earth and related environmental sciences, Remote sensing, Ground truth, Optical and acoustical sensors, Wasserbau (627), 010604 marine biology & hydrobiology, Geology, Ranging, Numerical models, Suspended particulate matter, Particulates, Regression, Oceanography, 13. Climate action, Ingenieurwissenschaften (620), Environmental science, Spatial variability, Sources of error
Abstract: (IF 3.25 [2018]; Q1); International audience; Measurement of suspended particulate matter concentration (SPMC) spanning large time and geographical scales have become a matter of growing importance in recent decades. At many places worldwide, complex observation platforms have been installed to capture temporal and spatial variability over scales ranging from cm (turbulent regimes) to whole basins. Long-term in situ measurements of SPMC involve one or more optical and acoustical sensors and, as the ground truth reference, gravimetric measurements of filtered water samples. The estimation of SPMC from optical and acoustical proxies generally results from the combination of a number of independent calibration measurements, as well as regression or inverse models. Direct or indirect measurements of SPMC are inherently associated with a number of uncertainties along the whole operation chain, the autonomous field deployment, to the analyses necessary for converting the observed proxy values of optical and acoustical signals to SPMC. Controlling uncertainties will become an important issue when the observational input comprises systems of sensors spanning large spatial and temporal scales. This will be especially relevant for detecting trends in the data with unambiguous statistical significance, separating anthropogenic impact from natural variations, or evaluating numerical models over a broad ensemble of different conditions using validated field data.The aim of the study is to present and discuss the benefits and limitations of using optical and acoustical backscatter sensors to acquire long-term observations of SPMC. Additionally, this study will formulate recommendations on how to best acquire quality-assured SPMC data sets, based on the challenges and uncertainties associated with those long-term observations. The main sources of error as well as the means to quantify and reduce the uncertainties associated with SPMC measurements are also illustrated.
Published: 2019
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93. Twenty years of satellite and in situ observations of surface chlorophyll-a from the northern Bay of Biscay to the eastern English Channel. Is the water quality improving?

Author: Gohin, Francis, Van der Zande, Dimitry, Tilstone, Gavin, Eleveld, Marieke, Lefebvre, Alain, Andrieux-Loyer, Françoise, Blauw, Anouk, Bryère, Philippe, Devreker, David, Garnesson, Philippe, Hernández Fariñas, Tania, Lamaury, Yoann, LAMPERT, LUIS, Lavigne, Héloïse, Menet-Nedelec, Florence, Pardo, Silvia, Saulquin, Bertrand, Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Royal Belgian Institute of Natural Sciences (RBINS), Plymouth Marine Laboratory (PML), Plymouth Marine Laboratory, Deltares [The Netherlands], ARGANS Limited, Laboratoire Laboratoire Environnement Ressources Morbihan Pays de Loire (LER/MPL), Analytic and Computational Research, Inc. - Earth Sciences (ACRI-ST), Sorbonne Université (SU), Service Hydrographique et Océanographique de la Marine (SHOM), and Ministère de la Défense
Subjects: [SDV.EE]Life Sciences [q-bio]/Ecology, environment, English Channel, Ocean colour, Phytoplankton, Chlorophyll-a, Satellite remote-sensing, European marine strategy framework directive, Bay of Biscay, Eutrophication assessment
Abstract: International audience; The variability of the phytoplankton biomass derived from daily chlorophyll-a (Chl-a) satellite images was investigated over the period 1998-2017 in the surface waters of the English Channel and the northern Bay of Biscay. Merged satellite (SeaWiFS-MODIS/Aqua-MERIS-VIIRS) Chl-a was calculated using the OC5 Ifremer algorithm which is optimized for moderately-turbid waters. The seasonal cycle in satellite-derived Chl-a was compared with in situ measurements made at seven coastal stations located in the southern side of the English Channel and in the northern Bay of Biscay. The results firstly showed that the satellite Chl-a product, derived from a suite of space-borne marine reflectance data, is in agreement with the coastal observations. For compliance with the directives of the European Union on water quality, time-series of 6-year moving average of Chl-a were assessed over the region. A clear decline was observed in the mean and 90th percentile of Chl-a at stations located in the mixed waters of the English Channel. The time-series at the stations located in the Bay of Biscay showed yearly fluctuations which correlated well with river discharge, but no overall Chl-a trend was observed. In the English Channel, the shape of the seasonal cycle in Chl-a changed over time. Narrower peaks were observed in spring at the end of the studied period, indicating an earlier limitation by nutrients. Monthly averages of satellite Chl-a, over the periods 1998-2003 and 2012-2017, exhibited spatial and temporal patterns in the evolution of the phytoplankton biomass similar to these observed at the seven coastal stations. Both the in situ and satellite Chl-a times-series showed a decrease in Chl-a in the English Channel in May, June and July. This trend in phytoplankton biomass is correlated with lower river discharges at the end of the period and a constant reduction in the riverine input of phosphorus through improvements in the water quality of the surrounding river catchments.
Published: 2019
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94. HF radar spectrum comparison method for current maps analysis

Author: Irène Mopin, Guillaume Sicot, Solène Jousset, Franck Dumas, Lab-STICC_ENSTAB_CID_PRASYS, Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT), Service Hydrographique et Océanographique de la Marine (SHOM), and Ministère de la Défense
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SPI]Engineering Sciences [physics], [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract: International audience; Oceanographic HF radar allows todescribe the hydrodynamics of a coastal area by providing a synoptic surface current map at high frequency and regular time steps (10mn). Its interest lies in its wide cover,the high frequency of acquisition and the regularity of the measurements (regardless of weather conditions). Nevertheless, the estimation of surface currents is not straightforward and requires processing of the data acquired by radarin order to extractsurface radial current. The methods involving a beamforming or methods known as direction finding are the most used in this scope. Unfortunately, these methods do not provide exactly unambiguous estimations. In addition, HF radar can be associate to others sensors (ADCP, satellites, etc.) or methods (numerical models) that also provide relevant information about the area of interest. Thus, the analysis of hydrodynamics behavior at various time scales (from tidal to pluriannual time scale) requires the analysis of all these sources of information in order to better catch and possibly improve the knowledge of this key area in between the bay of Biscay and the Celtic Sea.In this presentation, a method which intends to compare a current map to HF radar datawill be introduced. The surface current could come from any sensors that provides surface current map or from numerical simulations. This comparison is directly performed with the low level data acquired by the radars ; we would rather avoid the comparison to geophysical data (current themselves) in order to prevent from information loss due to the estimation process or due to geometrical configurations of the radars (geometrical dilution of precision). Indeed, this comparison is performed thanks to an analysis of the radar Doppler spectrum. Hence the comparison is done by radar and therefore only the radial component is studied at the same time. This presentation will focus on the impact of the met-oceanic (wind, waves, tides) conditions and will highlight the main differences observed from current map estimating from HF radar itself and from a high resolution numerical simulation. The area of interest for this study is the Iroise Sea on the west of Brittany in France where data have been acquiring since 2006. This large amount of data covering a wide span of environmental conditions has been fundamental to investigatethis area in a wide variety of hydrodynamical situations.
Published: 2019

95. Amélioration de la connaissance de la mesure des courants de surface par radar HF

Author: Irène Mopin, Guillaume Sicot, Solène Jousset, Franck Dumas, Lab-STICC_ENSTAB_CID_PRASYS, Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, and Briec, Marie
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SPI]Engineering Sciences [physics], [SPI] Engineering Sciences [physics], [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2019

96. Outlier detection for Multibeam echo sounder (MBES) data from past to present

Author: Jenner Etienne, Vincent Lucas, Le Deunf Julian, Billot Romain, Debese Nathalie, Schmitt Thierry, Guibourt Francois, Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Département Logique des Usages, Sciences sociales et Sciences de l'Information (IMT Atlantique - LUSSI), IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Lab-STICC_IMTA_CID_DECIDE, Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL), Lab-STICC_ENSTAB_CID_TOMS, Institut Mines-Télécom [Paris] (IMT), Laboratoire des Sciences de l'Image, de l'Informatique et de la Télédétection (LSIIT), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), and Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique)
Subjects: Computer science, 02 engineering and technology, computer.software_genre, 01 natural sciences, [INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI], 010104 statistics & probability, Data acquisition, Echo sounding, [STAT.ML]Statistics [stat]/Machine Learning [stat.ML], Machine learning, 0202 electrical engineering, electronic engineering, information engineering, Outlier detection, Bathymetry, [INFO]Computer Science [cs], 0101 mathematics, Cluster analysis, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Multibeam echo sounder data, Data processing, business.industry, [SDE.IE]Environmental Sciences/Environmental Engineering, Automation, [SDE]Environmental Sciences, 020201 artificial intelligence & image processing, Anomaly detection, Data mining, business, computer
Abstract: With the new data acquisition capabilities of latest MBES, the need of an automation data processing is more and more essential. The aim of this article is to present what kind of data processing we want to improve, what techniques were used in the past and how machine learning could help us now and in the future for a better bathymetric data processing.
Published: 2019
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97. Deontic Reasoning for Legal Ontologies

Author: Cheikh Kacfah Emani, Yannis Haralambous, Département Informatique (IMT Atlantique - INFO), IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Lab-STICC_IMTA_CID_DECIDE, Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL), and This work is funded by the Service hydrographique et océanographique de la marine (Shom) as part of the reizhmor project.
Subjects: Deontic logic, Computer science, [INFO.INFO-WB]Computer Science [cs]/Web, 0211 other engineering and technologies, Legal texts, 02 engineering and technology, Consistency (knowledge bases), Deontic reasoning, Base (topology), Epistemology, [INFO.INFO-NI]Computer Science [cs]/Networking and Internet Architecture [cs.NI], TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES, Proof theory, TheoryofComputation_LOGICSANDMEANINGSOFPROGRAMS, 021105 building & construction, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, [INFO.INFO-HC]Computer Science [cs]/Human-Computer Interaction [cs.HC], Semantic Web
Abstract: International audience; Many standards exist to formalize legal texts and rules. The same is true for legal ontologies. However, there is no proof theory to draw conclusions for these ontologically modeled rules. We address this gap by the proposal of a new modeling of deontic statements, and then we use this modeling to propose reasoning mechanisms to answer deontic questions i.e., questions like "Is it mandatory/permitted/prohibited to…"'. We also show that using this modeling, it is possible to check the consistency of a deontic rule base. This work stands as a first important step towards a proof theory over a deontic rule base.
Published: 2019
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98. Potential Vorticity diagnostics based on balances between volume integral and boundary conditions

Author: Aurélien Ponte, Yves Morel, Jonathan Gula, Centre Militaire d'Océanographie, Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense-Ministère de la Défense, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), and ANR-17-CE01-0006,EQUINOX,Séparation des mouvements quasi-géostrophiques et des ondes internes pour l'observation satellite haute résolution de l'Océan(2017)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Coordinate system, Boundary (topology), general circulation, Oceanography, boundary layers, 01 natural sciences, Volume integral, Potential vorticity, fronts, boundary conditions, Fronts, Computer Science (miscellaneous), Boundary value problem, 0105 earth and related environmental sciences, Physics, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Boundary conditions, 010505 oceanography, General circulation, Surface integral, Mechanics, Geotechnical Engineering and Engineering Geology, Vortex, Boundary layer, vortex, Boundary layers
Abstract: Taking advantage of alternative expressions for potential vorticity (PV) in divergence forms, we derive balances between volume integral of PV and boundary conditions, that are then applied to practical computations of PV: • We propose a new method for diagnosing the Ertel potential vorticity from model output, that preserves the balances; • We show how the expression of PV can be derived in general coordinate systems. This is here emphasised with isopycnic coordinates by generalising the PV expression to the general Navier-Stokes equations; • We propose a generalised derivation for the Haynes-McIntyre impermeability theorem, which highlights the role of the bottom boundary condition choice (e.g. no-slip vs free-slip) and mixing near the bottom boundary for the volume integral of PV. The implications of balances between volume integral of PV and boundary conditions are then analysed for specific processes at various scales: • At large scale, we show how an integral involving surface observations (derived from satellite observations) is linked to the integral of PV within a layer (between two isopycnals). This surface integral can be calculated for models and observations and can be used for validation; • At mesoscale or sub-mesoscale, we analyse the relationship between net PV anomalies and net surface density anomalies for idealised vortices and 2D fronts. This can help determining vortex or jet structures for idealised studies or empirical methodologies; • We also confirm and integrate previous results on the modification of PV within a bottom boundary layer into a single diagnostic taking into account the effect of density and velocity modifications by diabatic processes along the topography and diapycnal mixing within the boundary layer.
Published: 2019
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99. 3D phase-resolved wave modelling with a non-hydrostatic ocean circulation model

Author: Patrick Marsaleix, Héloïse Michaud, Claude Estournel, Laboratoire d'aérologie (LA), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Context (language use), Oceanography, 01 natural sciences, Wave model, Computer Science (miscellaneous), phase-resolved wave modelling, Bathymetry, 14. Life underwater, Rip current, non-hydrostatic, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010505 oceanography, wave breaking, Linear system, Breaking wave, ocean circulation model, Mechanics, Geotechnical Engineering and Engineering Geology, Circulation (fluid dynamics), 13. Climate action, [SDU]Sciences of the Universe [physics], rip currents, Parametrization, Geology
Abstract: International audience; A phase-resolved wave model is derived from an ocean circulation model for the purpose of studying wave-current effects in nearshore zones. One challenge is to adapt the circulation model to the specificities of wave physics. This mainly concerns the consideration of nonhydrostatic effects and the parametrization of wave breaking. The non-hydrostatic pressure is calculated using the artificial compressibility method (ACM). The ACM-induced errors on wave dispersion properties are examined in detail in the context of the linear theory using idealized test cases. The possible compromise between the precision achieved on nonhydrostatic physics and the adjustable CPU cost of the ACM method is looked at in detail. The modification of the wave characteristics by the bathymetric slope and the breaking of waves are then examined from a linear slope beach laboratory experiment. Finally the model is evaluated on the issue of rip currents and their feedback on the wave field using a laboratory experiment of a beach with a bar intersected by channels.
Published: 2019
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100. Mesoscale Morphological Changes of Nearshore Sand Banks since the Early 19th Century, and Their Influence on Coastal Dynamics, Northern France

Author: Arnaud Héquette, Alexa Latapy, Nicolas Weber, Jean-Baptiste Robin-Chanteloup, Nicolas Pouvreau, Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, and Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord])
Subjects: 010504 meteorology & atmospheric sciences, Mesoscale meteorology, macrotidal coast, Ocean Engineering, 010502 geochemistry & geophysics, 01 natural sciences, tidal sand banks, lcsh:Oceanography, Hydrographic survey, lcsh:VM1-989, Bathymetry, lcsh:GC1-1581, 14. Life underwater, Seabed, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Water Science and Technology, Civil and Structural Engineering, Shore, geography, Dover Strait, geography.geographical_feature_category, lcsh:Naval architecture. Shipbuilding. Marine engineering, Sediment, Southern North Sea, Oceanography, 13. Climate action, shoreface evolution, Erosion, Submarine pipeline, Geology
Abstract: Tidal sand banks are common along the coast of northern France facing the North Sea, where they form linear shore-parallel or slightly oblique sand bodies from shallow coastal areas to depths of tens of meters. Hydrographic surveys have been carried out since the 1830s for mapping the seabed of the coastal zone. An analysis of the bathymetry evolution shows significant morphological changes have occurred across the shoreface since the early 19th century, largely due to cross-shore and longshore sand bank migration. Our results show that nearshore sand banks mainly migrated onshore and gained sediment, especially during the 20th century, acting as temporary sediment sinks, which can in turn serve as sand sources for providing sediment to the coast. Alongshore, the migration and elongation of sand banks can be related to tidal asymmetry that is mostly directed to the east-north-east in the region. Shore-perpendicular movement can likely be explained by the action of shore-normal storm-waves in the nearshore zone after their refraction over shallow offshore sand banks. A seaward displacement of sand banks was also observed. This may be related to the combined action of waves and tidal currents which can induce erosion on one side of the bank, decreasing its width, and eventually leading to its seaward migration. Our observations point out that some nearshore sand banks respond to the action of currents and waves, and interact between each other via feedback morphodynamic processes induced by sand bank morphological changes. The substantial morphologic changes that affected the nearshore zone of northern France during the last centuries probably had large impacts on coastal hydrodynamics and associated shoreline evolution.
Published: 2019
Full Text: View/download PDF

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