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1. Designing a fully-tunable and versatile TKE-l turbulence parameterization for atmospheric models

Author

VIGNON, Étienne, primary, ARJDAL, Khadija, additional, Cheruy, Frederique, additional, coulondecorzens, Maëlle, additional, Dehondt, Clément, additional, Dubos, Thomas, additional, Fromang, Sébastien, additional, Hourdin, Frédéric, additional, Lange, Lucas, additional, Raillard, Lea, additional, Rivière, Gwendal, additional, Roehrig, Romain, additional, Sima, Adriana, additional, Spiga, Aymeric, additional, and Tiengou, Pierre, additional

Published
2024
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3. Towards an advanced representation of precipitation over Morocco in a global climate model with resolution enhancement and empirical run‐time bias corrections.

Author

Balhane, Saloua, Cheruy, Frédérique, Driouech, Fatima, El Rhaz, Khalid, Idelkadi, Abderrahmane, Sima, Adriana, Vignon, Étienne, Drobinski, Philippe, and Chehbouni, Abdelghani

Subjects
CLIMATE change models, PRECIPITATION variability, ATMOSPHERIC models, DOWNSCALING (Climatology), WATER shortages, PRECIPITATION gauges
Abstract

Morocco, as a Mediterranean and North African country, is acknowledged as a climate change hotspot, where increased drought and related water resource shortages present a real challenge for human and natural systems. However, its geographic position and regional characteristics make the simulation of the distribution and variability of precipitation particularly challenging in the region. In this study, we propose an approach where the Laboratoire de Météorologie Dynamique Zoom (LMDZ) GCM is run with a stretched grid configuration developed with enhanced resolution (35 km) over the region, and we apply run‐time bias correction to deal with the atmospheric model's systematic errors on large‐scale circulation. The bias‐correction terms for wind and temperature are built using the climatological mean of the adjustment terms on tendency errors in an LMDZ simulation relaxed towards ERA5 reanalyses. The free reference run with the zoomed configuration is compared to two bias‐corrected runs. The free run exhibits noticeable improvements in mean low‐level circulation, high frequency variability and moisture transport and compares favourably to precipitation observations at the local scale. The mean simulated climate is substantially improved after bias correction w.r.t. to the uncorrected runs. At the regional scale, the bias‐correction showed improvements in moisture transport and precipitation distribution, but no noticeable effect was observed in mean precipitation amounts, interannual variability and extreme events. To address the latter, model tuning after grid refinement and developing more "scale‐aware" parameterizations are necessary. The observed improvements on the large‐scale circulation suggest that the run‐time bias correction can be used to drive regional climate models for a better representation of regional and local climate. It can also be combined with "a posteriori" bias correction methods to improve local precipitation simulation, including extreme events. [ABSTRACT FROM AUTHOR]

Published
2024
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6. A PHILOSOPHICAL VIEW OF GOD, FAITH AND UNBELIEF IN 21ST CENTURY SOCIETY.

Author

Sima, Adriana

Subjects
*GOD, *FAITH, *ATHEISM, *VALUES (Ethics), *DECISION making
Abstract

Faith in God also enables individuals to make sense of their lives in the midst of chaos and to find meaning and purpose in life's challenges, a sense of peace and security, especially during difficult times, It can provide hope for a brighter future and a sense of assurance that no matter what life throws our way, God is always with us, knowing that God will never leave them and that He has a plan for their lives. The debate on creation versus evolution is an ongoing, heated debate that has been going on for many years. The debate is between those who believe that God created the universe and those who believe that evolution is the process by which the universe was created. Creationists believe that the Bible is literal and that God created the world in six days. Evolutionists believe that the universe developed over billions of years through natural processes. The debate is ongoing because there is no clear answer to the question of how the universe was created. The evidence for both sides is inconclusive, with no one side able to definitively prove their point of view. The issue of faith and unbelief in God in 21st century society is a complex one. It is important to remember that everyone has the right to make their own decisions when it comes to their beliefs and that there is no one right answer, the important thing is to respect the beliefs of others, no matter what they may be. Alternative sources of spiritual guidance, such as meditation, mindfulness and yoga can take the place of a higher, omniscient and omnipresent Being to whom are attributed all the positive traits that he imprints on people in the form of moral and ethical values, without denying the positive aspects that they have on the human mind and on physical well-being? Therewith, the internet has provided access to a variety of religious perspectives, so more people are exposed to different beliefs and the idea of religious diversity. There is also a growing sense of skepticism about faith among many people. With the rise of science and the prevalence of "fake news", people are increasingly questioning the validity of religious claims. In the last 10 years, with the emergence of several types of manifestations, several surveys have been conducted in many countries of the world regarding belief in God, the weight of religion in everyday life and people's attitude toward faith. The results were surprising because it could be observed that more and more people perceive the relation to faith and to the Divinity in a completely different way than in the previous centuries. Given the above, it is necessary to try to find answers to some questions that may give us a better understanding of the human-Divinity relationship in the society of the 21st century. Does today's society still believe in God and the moral laws promoted by the church? When and why did people begin to give up belief in God? Why is there a growing sense of skepticism about faith? Are people now more likely to question the traditional beliefs? Do people belive in God in 21st century society or this is the century of unbelif and theism? 21st century society - a society of faith in God, a society of unbelif or a society of atheism? Faith in God remains a powerful force in the world today? [ABSTRACT FROM AUTHOR]

Published
2023
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9. Presentation and Evaluation of the IPSL-CM6A-LR Climate Model

Author

Boucher, Olivier, Servonnat, Jérôme, Albright, Anna Lea, Aumont, Olivier, Balkanski, Yves, Bastrikov, Vladislav, Bekki, Slimane, Bonnet, Rémy, Bony, Sandrine, Bopp, Laurent, Braconnot, Pascale, Brockmann, Patrick, Cadule, Patricia, Caubel, Arnaud, Cheruy, Frédérique, Codron, Francis, Cozic, Anne, Cugnet, David, d'Andrea, Fabio, Davini, Paolo, de Lavergne, Casimir, Denvil, Sébastien, Deshayes, Julie, Devilliers, Marion, Ducharne, Agnès, Dufresne, Jean-Louis, Dupont, Eliott, Éthé, Christian, Fairhead, Laurent, Falletti, Lola, Flavoni, Simona, Foujols, Marie-Alice, Gardoll, Sébastien, Gastineau, Guillaume, Ghattas, Josefine, Grandpeix, Jean-Yves, Guenet, Bertrand, Guez, Lionel, Guilyardi, Éric, Guimberteau, Matthieu, Hauglustaine, Didier, Hourdin, Frédéric, Idelkadi, Abderrahmane, Joussaume, Sylvie, Kageyama, Masa, Khodri, Myriam, Krinner, Gerhard, Lebas, Nicolas, Levavasseur, Guillaume, Lévy, Claire, Li, Laurent, Lott, François, Lurton, Thibaut, Luyssaert, Sebastiaan, Madec, Gurvan, Madeleine, Jean-Baptiste, Maignan, Fabienne, Marchand, Marion, Marti, Olivier, Mellul, Lidia, Meurdesoif, Yann, Mignot, Juliette, Musat, Ionela, Ottle, Catherine, Peylin, Philippe, Planton, Yann, Polcher, Jan, Rio, Catherine, Rochetin, Nicolas, rousset, clement, Rousset, Clément, Sepulchre, Pierre, Sima, Adriana, Swingedouw, Didier, Thiéblemont, Rémi, Traore, Abdoul Khadre, Vancoppenolle, Martin, Vial, Jessica, Vialard, Jérôme, Viovy, Nicolas, Vuichard, Nicolas, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), 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, 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), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), 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)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-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)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Nucleus for European Modeling of the Ocean (NEMO R&D ), 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)), 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), 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)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), STRATO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-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)-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), Modélisation du climat (CLIM), Calcul Scientifique (CALCULS), Océan et variabilité du climat (VARCLIM), Istituto di Scienze dell'Atmosfera e Del Clima [Torino] (isac), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), 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), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols (METIS), École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-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), University of Amsterdam [Amsterdam] (UvA), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-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)-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 -Centre National de la Recherche Scientifique (CNRS), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), ANR-17-EURE-0006,IPSL-CGS,IPSL Climate graduate school(2017), ANR-15-JCLI-0004,GOTHAM,Globally Observed Teleconnections and their role and representation in Hierarchies of Atmospheric Models(2015), ANR-18-CE01-0012,ARiSE,Rôle de la non-linéarité de la réponse atmosphérique à la température de l'océan dans la physique d'ENSO (El Niño Oscillation Australe)(2018), ANR-13-MONU-0008,CONVERGENCE,Convergence en Science du Climat à l'ère du Big Data et des challenges de l'Exascale.(2013), ANR-18-MPGA-0001,ARCHANGE,Changement climatique et Arctique et circulation océanique globale(2018), European Project: 641816,H2020,H2020-SC5-2014-two-stage,CRESCENDO(2015), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-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)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Sorbonne Université (SU), École normale supérieure - Paris (ENS Paris)-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), Consiglio Nazionale delle Ricerche (CNR), UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), 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), Sorbonne Université (SU)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), MOSAIC (MOSAIC), Institut FRESNEL (FRESNEL), 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), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Météo France, 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), École pratique des hautes études (EPHE), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-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)-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)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), 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), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), 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), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), and Systems Ecology

Subjects
010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, 010502 geochemistry & geophysics, climate model, IPSL‐CM6A‐LR, 01 natural sciences, Carbon cycle, lcsh:Oceanography, climate metrics, Range (statistics), SDG 13 - Climate Action, Environmental Chemistry, lcsh:GC1-1581, Precipitation, lcsh:Physical geography, ComputingMilieux_MISCELLANEOUS, CMIP6, 0105 earth and related environmental sciences, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Global and Planetary Change, Coupled model intercomparison project, Intertropical Convergence Zone, 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Climatology, Middle latitudes, General Earth and Planetary Sciences, Environmental science, Climate sensitivity, climate sensitivity, Climate model, lcsh:GB3-5030, IPSL-CM6A-LR
Abstract

International audience This study presents the global climate model IPSL-CM6A-LR developed at Institut Pierre-Simon Laplace (IPSL) to study natural climate variability and climate response to natural and anthropogenic forcings as part of the sixth phase of the Coupled Model Intercomparison Project (CMIP6). This article describes the different model components, their coupling, and the simulated climate in comparison to previous model versions. We focus here on the representation of the physical climate along with the main characteristics of the global carbon cycle. The model's climatology, as assessed from a range of metrics (related in particular to radiation, temperature, precipitation, and wind), is strongly improved in comparison to previous model versions. Although they are reduced, a number of known biases and shortcomings (e.g., double Intertropical Convergence Zone [ITCZ], frequency of midlatitude wintertime blockings, and El Niño–Southern Oscillation [ENSO] dynamics) persist. The equilibrium climate sensitivity and transient climate response have both increased from the previous climate model IPSL-CM5A-LR used in CMIP5. A large ensemble of more than 30 members for the historical period (1850–2018) and a smaller ensemble for a range of emissions scenarios (until 2100 and 2300) are also presented and discussed.

Published
2020

15. Effective radiative forcing and adjustments in CMIP6 models

Author

Smith, Christopher J., primary, Kramer, Ryan J., additional, Myhre, Gunnar, additional, Alterskjær, Kari, additional, Collins, William, additional, Sima, Adriana, additional, Boucher, Olivier, additional, Dufresne, Jean-Louis, additional, Nabat, Pierre, additional, Michou, Martine, additional, Yukimoto, Seiji, additional, Cole, Jason, additional, Paynter, David, additional, Shiogama, Hideo, additional, O'Connor, Fiona M., additional, Robertson, Eddy, additional, Wiltshire, Andy, additional, Andrews, Timothy, additional, Hannay, Cécile, additional, Miller, Ron, additional, Nazarenko, Larissa, additional, Kirkevåg, Alf, additional, Olivié, Dirk, additional, Fiedler, Stephanie, additional, Lewinschal, Anna, additional, Mackallah, Chloe, additional, Dix, Martin, additional, Pincus, Robert, additional, and Forster, Piers M., additional

Published
2020
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16. Fast responses on pre-industrial climate from present-day aerosols in a CMIP6 multi-model study

Author

Zanis, Prodromos, primary, Akritidis, Dimitris, additional, Georgoulias, Aristeidis K., additional, Allen, Robert J., additional, Bauer, Susanne E., additional, Boucher, Olivier, additional, Cole, Jason, additional, Johnson, Ben, additional, Deushi, Makoto, additional, Michou, Martine, additional, Mulcahy, Jane, additional, Nabat, Pierre, additional, Olivié, Dirk, additional, Oshima, Naga, additional, Sima, Adriana, additional, Schulz, Michael, additional, Takemura, Toshihiko, additional, and Tsigaridis, Konstantinos, additional

Published
2020
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17. Implementation of the CMIP6 Forcing Data in the IPSL‐CM6A‐LR Model

Author

Lurton, Thibaut, primary, Balkanski, Yves, additional, Bastrikov, Vladislav, additional, Bekki, Slimane, additional, Bopp, Laurent, additional, Braconnot, Pascale, additional, Brockmann, Patrick, additional, Cadule, Patricia, additional, Contoux, Camille, additional, Cozic, Anne, additional, Cugnet, David, additional, Dufresne, Jean‐Louis, additional, Éthé, Christian, additional, Foujols, Marie‐Alice, additional, Ghattas, Josefine, additional, Hauglustaine, Didier, additional, Hu, Rong‐Ming, additional, Kageyama, Masa, additional, Khodri, Myriam, additional, Lebas, Nicolas, additional, Levavasseur, Guillaume, additional, Marchand, Marion, additional, Ottlé, Catherine, additional, Peylin, Philippe, additional, Sima, Adriana, additional, Szopa, Sophie, additional, Thiéblemont, Rémi, additional, Vuichard, Nicolas, additional, and Boucher, Olivier, additional

Published
2020
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18. A CMIP6 multi-model study of fast responses on pre-industrial climate due to present-day aerosols

Author

Zanis, Prodromos, primary, Akritidis, Dimitris, additional, Georgoulias, Aristeidis K., additional, Allen, Robert J., additional, Bauer, Susanne E., additional, Boucher, Olivier, additional, Cole, Jason, additional, Johnson, Ben, additional, Deushi, Makoto, additional, Michou, Martine, additional, Mulcahy, Jane, additional, Nabat, Pierre, additional, Olivie, Dirk, additional, Oshima, Naga, additional, Sima, Adriana, additional, Schulz, Michael, additional, and Takemura, Toshihiko, additional

Published
2020
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19. Supplementary material to "Fast responses on pre-industrial climate from present-day aerosols in a CMIP6 multi-model study"

Author

Zanis, Prodromos, primary, Akritidis, Dimitris, additional, Georgoulias, Aristeidis K., additional, Allen, Robert J., additional, Bauer, Susanne E., additional, Boucher, Olivier, additional, Cole, Jason, additional, Johnson, Ben, additional, Deushi, Makoto, additional, Michou, Martine, additional, Mulcahy, Jane, additional, Nabat, Pierre, additional, Olivie, Dirk, additional, Oshima, Naga, additional, Sima, Adriana, additional, Schulz, Michael, additional, and Takemura, Toshihiko, additional

Published
2020
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20. Supplementary material to "Effective radiative forcing and adjustments in CMIP6 models"

Author

Smith, Christopher J., primary, Kramer, Ryan J., additional, Myhre, Gunnar, additional, Alterskjær, Kari, additional, Collins, William, additional, Sima, Adriana, additional, Boucher, Olivier, additional, Dufresne, Jean-Louis, additional, Nabat, Pierre, additional, Michou, Martine, additional, Yukimoto, Seiji, additional, Cole, Jason, additional, Paynter, David, additional, Shiogama, Hideo, additional, O'Connor, Fiona M., additional, Robertson, Eddy, additional, Wiltshire, Andy, additional, Andrews, Timothy, additional, Hannay, Cécile, additional, Miller, Ron, additional, Nazarenko, Larissa, additional, Kirkevåg, Alf, additional, Olivié, Dirk, additional, Fiedler, Stephanie, additional, Pincus, Robert, additional, and Forster, Piers M., additional

Published
2020
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21. Impact of dust in PMIP-CMIP6 mid-Holocene simulations with the IPSL model.

Author

Braconnot, Pascale, Albani, Samuel, Balkanski, Yves, Cozic, Anne, Kageyama, Masa, Sima, Adriana, Marti, Olivier, and Peterschmitt, Jean-Yves

Abstract

We investigate the impact of reduced dust during mid-Holocene using simulations with the IPSL model. We consider simulations where dust is either prescribed from an IPSL PI simulation or from CESM simulations (Albani et al., 2015). In addition, we also consider an extreme mid Holocene case where dust is suppressed. We focus on the estimation of the dust radiative effects and the relative responses of the African and Indian monsoon, showing how local dust forcing or orography affect atmospheric temperature profiles, humidity and precipitation. Compared to previous simulations with the IPSL model the results show only minor improvements for the mid Holocene simulation over large regions despite the fact that the IPSLCM6-LR version of the IPSL model is in better agreement with modern observations. The effect of dust has little impact on the model-data comparisons. Our analyses confirm the peculiar role of dust radiative effect over bright surfaces such as African deserts compared to other regions due to the change of sign of the dust radiative effect at the top-of-atmosphere for high surface albedo. We also highlight a strong dependence on the dust pattern. In particular the relative dust forcing between West Africa and the middle east impacts the relative climate response between India and Africa and between Africa, the western tropical Atlantic and the Atlantic meridional circulation. Dust patterns should thus receive a wider attention to fully understand the changes in the dust cycle and forcing during mid Holocene [ABSTRACT FROM AUTHOR]

Published
2020
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22. (MIS3 & 2) millennial oscillations in Greenland dust and Eurasian aeolian records – A paleosol perspective

Author

Rousseau, Denis-Didier, Boers, Niklas, Sima, Adriana, Bigler, Matthias, Lagroix, France, Taylor, Samuel, and Antoine, Pierre

Subjects
Dust, Climatic changes, Paleoclimatology, Paleopedology
Abstract

Since their discovery, the abrupt climate changes that punctuated the last glacial period (∼110.6–14.62 ka) have attracted considerable attention. Originating in the North-Atlantic area, these abrupt changes have been recorded in ice, marine and terrestrial records all over the world, but especially in the Northern Hemisphere, with various environmental implications. Ice-core records of unprecedented temporal resolution from northern Greenland allow to specify the timing of these abrupt changes, which are associated with sudden temperature increases in Greenland over a few decades, very precisely. The continental records have, so far, been mainly interpreted in terms of temperature, precipitation or vegetation changes between the relatively warm “Greenland Interstadials” (GI) and the cooler “Greenland Stadials” (GS). Here we compare records from Greenland ice and northwestern European eolian deposits in order to establish a link between GI and the soil development in European mid-latitudes, as recorded in loess sequences. For the different types of observed paleosols, we use the correlation with the Greenland records to propose estimates of the maximum time lapses needed to achieve the different degrees of maturation and development. To identify these time lapses more precisely, we compare two independent ice-core records: δ¹⁸O and dust concentration, indicating variations of atmospheric temperature and dustiness in the Greenland area, respectively. Our method slightly differs from the definition of a GI event duration applied in other studies, where the sharp end of the δ¹⁸O decrease alone defines the end of a GI. We apply the same methodology to both records (i.e., the GIs are defined to last from the beginning of the abrupt δ¹⁸O increase or dust concentration decrease until the time when δ¹⁸O or dust recur to their initial value before the GI onset), determined both visually and algorithmically, and compare them to published estimates of GI timing and duration. The duration of the GI and consequently the maximum time for paleosol development varies between 200 and 4200 years when visually determined and between 200 and 4800 years when estimated algorithmically for GI 17 to 2, i.e. an interval running from 60 ka to 23 ka b2k (age before 2000 AD). Furthermore, we investigate the abruptness of the transition from stadial to interstadial conditions, which initiates the paleosol development. The average transition duration is 55.4 ± 16.1 (56.8 ± 19.6) years when determined visually, and 36.4 ± 13.4 (60.00 ± 21.2) years when determined algorithmically for the δ¹⁸O (dust concentration). The δ¹⁸O increases correspond to a mean temperature difference of 11.8 °C on the top of the Greenland ice sheet, associated with substantial reorganizations of the ecosystems in mid-latitude Europe.

Published
2017
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27. European glacial dust deposits: Geochemical constraints on atmospheric dust cycle modeling

Author

Rousseau, Denis-Didier, Chauvel, Catherine, Sima, Adriana, Hatté, Christine, Lagroix, France, Antoine, Pierre, Balkanski, Yves, Fuchs, Markus, Mellett, Claire, Kageyama, Masa, Ramstein, Gilles, Lang, Andreas, 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-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), Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], Laboratoire d'Accidentologie et de Biomécanique, RENAULT-PSA Peugeot Citroën (PSA), Institut des Sciences de la Terre (ISTerre), Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), 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)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Géochrononologie Traceurs Archéométrie (GEOTRAC), 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)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-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)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de géographie physique : Environnements Quaternaires et Actuels (LGP), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), Department of Geography, Justus-Liebig- University, Justus-Liebig-Universität Gießen = Justus Liebig University (JLU), British Geological Survey [Edinburgh], British Geological Survey (BGS), Modélisation du climat (CLIM), University of Liverpool, 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), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Justus-Liebig-Universität Gießen (JLU), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Panthéon-Sorbonne (UP1)

Subjects
[SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry
Abstract

International audience; For a long time global paleodust numerical simulations have greatly underestimated dust sources other than modern deserts. Recent modeling experiments incorporating glaciogenic sources of dust have positively improved the agreement between model and paleodust data. This highlights the importance of accurately representing all areas potentially subjected to deflation during an investigated interval. Geochemical results, obtained from European loess sequences collected along a 50°N transect, combined with dust emission simulations reveal the geographical distribution of the most important European dust sources between 34 ka and 18 ka. We demonstrate that most European dust traveled only a few hundred kilometers or less within the boundary layer from its source before deposition. We conclude that our results encourage acquisition of similar geochemical data for other relevant areas in the world. Further, they could provide critical constraints to benchmark atmospheric models, contributing to improve their performance in simulating dust cycle and associated climate feedbacks.

Published
2014

29. Modellierung von Sauerstoffisotopen im Inlandeis im Zusammenhang mit quartären Eisvolumenschwankungen

Author

Sima, Adriana, Schulz, Michael, and Oerlemans, Johannes

Subjects
Quaternary, Younger Dryas, oxygen isotopes, ocean modeling, ice-sheet modeling, ddc:29
Abstract

Climate change through the Quaternary was dominated by repeated build-up and retreat of large ice sheets, especially in the Northern Hemisphere. The best indicator for past variations of global ice volume is the oxygen-isotopic composition (d18O) of seawater (dw) recorded in foraminiferal calcite in marine sediments. But the interpretation calcite-d18O (dc) records is not straightforward, mainly because dc depends on both dw and seawater temperature. Furthermore, in common paleoceanographic practice the relationship between dw and ice volume is assumed linear, but two main factors may induce considerable nonlinearity: the mean isotopic composition of ice, which varies during a glacial cycle, and the ocean circulation. In the present study, these two factors were investigated at glacial-interglacial timescale using a 2.5-dimensional thermomechanical ice-sheet model including oxygen-isotope transport, combined with different ocean models. First, using a well-mixed ocean, it was found that the effect of mean-ice d18O variations can be neglected in reconstructing ice volume from marine d18O records. Second, the effect of ocean circulation was investigated qualitatively by replacing the well-mixed ocean by a spatially-resolved ocean model. It was concluded that the ocean circulation is an important element to be taken into account in the climatic and stratigraphic interpretation of dc records and that leads/lags inferred on the basis of proxies depending on more than one physical variable, such as dc, can be misleading in interpreting causal relationships. Finally, the interaction between climate variability at orbital and millennial timescales was investigated in order to gain further understanding of the origin of d18O variations in marine sediments and ice cores. It was found that YD-type events may occur during any deglaciation of the past 800 kyr, so that YD is probably not a one-time event, but an intrinsic feature of the climate change at millennial timescales.

Published
2005

35. Eurasian contribution to the last glacial dust cycle: how are loess sequences built?

Author

Rousseau, Denis-Didier, Svensson, Anders, Bigler, Matthias, Sima, Adriana, Steffensen, Jorgen Peder, and Boers, Niklas

Subjects
Loess--Environmental aspects, 13. Climate action, Dust, Climatic changes, Paleoclimatology
Abstract

The last 130 000 years have been marked by pronounced millennial-scale climate variability, which strongly impacted the terrestrial environments of the Northern Hemisphere, especially at middle latitudes. Identifying the trigger of these variations, which are most likely associated with strong couplings between the ocean and the atmosphere, still remains a key question. Here, we show that the analysis of δ¹⁸O and dust in the Greenland ice cores, and a critical study of their source variations, reconciles these records with those observed on the Eurasian continent. We demonstrate the link between European and Chinese loess sequences, dust records in Greenland, and variations in the North Atlantic sea ice extent. The sources of the emitted and transported dust material are variable and relate to different environments corresponding to present desert areas, but also hidden regions related to lower sea level stands, dry rivers, or zones close to the frontal moraines of the main Northern Hemisphere ice sheets. We anticipate our study to be at the origin of more sophisticated and elaborated investigations of millennial and sub-millennial continental climate variability in the Northern Hemisphere.

36. European glacial dust deposits: Geochemical constraints on atmospheric dust cycle modeling

Author

Rousseau, Denis-Didier, Chauvel, Catherine, Sima, Adriana, Hatté, Christine, Lagroix, France, Antoine, Pierre, Balkanski, Yves, Fuchs, Markus, Mellett, Claire, Kageyama, Masa, Ramstein, Gilles, and Lang, Andreas

Subjects
Loess--Environmental aspects, Geochemistry, 13. Climate action, Dust, FOS: Earth and related environmental sciences, Paleoclimatology
Abstract

For a long time global paleodust numerical simulations have greatly underestimated dust sources other than modern deserts. Recent modeling experiments incorporating glaciogenic sources of dust have positively improved the agreement between model and paleodust data. This highlights the importance of accurately representing all areas potentially subjected to deflation during an investigated interval. Geochemical results, obtained from European loess sequences collected along a 50°N transect, combined with dust emission simulations reveal the geographical distribution of the most important European dust sources between 34 ka and 18 ka. We demonstrate that most European dust traveled only a few hundred kilometers or less within the boundary layer from its source before deposition. We conclude that our results encourage acquisition of similar geochemical data for other relevant areas in the world. Further, they could provide critical constraints to benchmark atmospheric models, contributing to improve their performance in simulating dust cycle and associated climate feedbacks.

37. Dynamics and sources of last glacial aeolian deposition in southwest France derived from dune patterns, grain-size gradients and geochemistry, and reconstruction of efficient wind directions

Author

Sitzia, Luca, Bertran, Pascal, Sima, Adriana, Chery, Philippe, Queffelec, Alain, and Rousseau, Denis-Didier

Subjects
Eolian processes, Geochemistry, Last Glacial Maximum, 13. Climate action, Sand dunes, FOS: Earth and related environmental sciences, 15. Life on land
Abstract

Dune pattern, grain-size gradients and geochemistry were used to investigate the sources and dynamics of aeolian deposition during the last glacial in southwest France. The coversands form widespread fields of low-amplitude ridges (zibars), whereas Younger Dryas parabolic dunes mainly concentrate in corridors and along rivers. Spatial modelling of grain-size gradients combined with geochemical analysis points to a genetic relationship between coversands and loess, the latter resulting primarily from dust produced by aeolian abrasion of the coversands. The alluvium of the Garonne river provided also significant amounts of dust at a more local scale. The geochemical composition of loess shows much lower scattering than that of coversands, due to stronger homogenisation during transport in the atmosphere. Overall, sandy loess and loess deposits decrease in thickness away from the coversands. Dune orientation and grain-size gradients suggest that the efficient winds blew respectively from the W to the NW during the glacial, and the W-SW during the Younger Dryas. A comparison between the wind directions derived from the proxy data and those provided by palaeoclimatic simulations suggests a change of the main transport season. Ground surface conditions and their evolution throughout the year, i.e. the length of the season with snow and frozen or moist topsoil, and the seasonal distribution of wind speeds able to cause deflation are thought to have been the main factors that controlled the transport season in the study area.

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