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1. Altimetry for the future: Building on 25 years of progress

Author

Abdalla, Saleh, Abdeh Kolahchi, Abdolnabi, Ablain, Michaël, Adusumilli, Susheel, Aich Bhowmick, Suchandra, Alou-Font, Eva, Amarouche, Laiba, Andersen, Ole Baltazar, Antich, Helena, Aouf, Lotfi, Arbic, Brian, Armitage, Thomas, Arnault, Sabine, Artana, Camila, Aulicino, Giuseppe, Ayoub, Nadia, Badulin, Sergei, Baker, Steven, Banks, Chris, Bao, Lifeng, Barbetta, Silvia, Barceló-Llull, Bàrbara, Barlier, François, Basu, Sujit, Bauer-Gottwein, Peter, Becker, Matthias, Beckley, Brian, Bellefond, Nicole, Belonenko, Tatyana, Benkiran, Mounir, Benkouider, Touati, Bennartz, Ralf, Benveniste, Jérôme, Bercher, Nicolas, Berge-Nguyen, Muriel, Bettencourt, Joao, Blarel, Fabien, Blazquez, Alejandro, Blumstein, Denis, Bonnefond, Pascal, Borde, Franck, Bouffard, Jérôme, Boy, François, Boy, Jean-Paul, Brachet, Cédric, Brasseur, Pierre, Braun, Alexander, Brocca, Luca, Brockley, David, Brodeau, Laurent, Brown, Shannon, Bruinsma, Sean, Bulczak, Anna, Buzzard, Sammie, Cahill, Madeleine, Calmant, Stéphane, Calzas, Michel, Camici, Stefania, Cancet, Mathilde, Capdeville, Hugues, Carabajal, Claudia Cristina, Carrere, Loren, Cazenave, Anny, Chassignet, Eric P., Chauhan, Prakash, Cherchali, Selma, Chereskin, Teresa, Cheymol, Cecile, Ciani, Daniele, Cipollini, Paolo, Cirillo, Francesca, Cosme, Emmanuel, Coss, Steve, Cotroneo, Yuri, Cotton, David, Couhert, Alexandre, Coutin-Faye, Sophie, Crétaux, Jean-François, Cyr, Frederic, d’Ovidio, Francesco, Darrozes, José, David, Cedric, Dayoub, Nadim, De Staerke, Danielle, Deng, Xiaoli, Desai, Shailen, Desjonqueres, Jean-Damien, Dettmering, Denise, Di Bella, Alessandro, Díaz-Barroso, Lara, Dibarboure, Gerald, Dieng, Habib Boubacar, Dinardo, Salvatore, Dobslaw, Henryk, Dodet, Guillaume, Doglioli, Andrea, Domeneghetti, Alessio, Donahue, David, Dong, Shenfu, Donlon, Craig, Dorandeu, Joël, Drezen, Christine, Drinkwater, Mark, Du Penhoat, Yves, Dushaw, Brian, Egido, Alejandro, Erofeeva, Svetlana, Escudier, Philippe, Esselborn, Saskia, Exertier, Pierre, Fablet, Ronan, Falco, Cédric, Farrell, Sinead Louise, Faugere, Yannice, Femenias, Pierre, Fenoglio, Luciana, Fernandes, Joana, Fernández, Juan Gabriel, Ferrage, Pascale, Ferrari, Ramiro, Fichen, Lionel, Filippucci, Paolo, Flampouris, Stylianos, Fleury, Sara, Fornari, Marco, Forsberg, Rene, Frappart, Frédéric, Frery, Marie-laure, Garcia, Pablo, Garcia-Mondejar, Albert, Gaudelli, Julia, Gaultier, Lucile, Getirana, Augusto, Gibert, Ferran, Gil, Artur, Gilbert, Lin, Gille, Sarah, Giulicchi, Luisella, Gómez-Enri, Jesús, Gómez-Navarro, Laura, Gommenginger, Christine, Gourdeau, Lionel, Griffin, David, Groh, Andreas, Guerin, Alexandre, Guerrero, Raul, Guinle, Thierry, Gupta, Praveen, Gutknecht, Benjamin D., Hamon, Mathieu, Han, Guoqi, Hauser, Danièle, Helm, Veit, Hendricks, Stefan, Hernandez, Fabrice, Hogg, Anna, Horwath, Martin, Idžanović, Martina, Janssen, Peter, Jeansou, Eric, Jia, Yongjun, Jia, Yuanyuan, Jiang, Liguang, Johannessen, Johnny A., Kamachi, Masafumi, Karimova, Svetlana, Kelly, Kathryn, Kim, Sung Yong, King, Robert, Kittel, Cecile M.M., Klein, Patrice, Klos, Anna, Knudsen, Per, Koenig, Rolf, Kostianoy, Andrey, Kouraev, Alexei, Kumar, Raj, Labroue, Sylvie, Lago, Loreley Selene, Lambin, Juliette, Lasson, Léa, Laurain, Olivier, Laxenaire, Rémi, Lázaro, Clara, Le Gac, Sophie, Le Sommer, Julien, Le Traon, Pierre-Yves, Lebedev, Sergey, Léger, Fabien, Legresy, Benoı̂t, Lemoine, Frank, Lenain, Luc, Leuliette, Eric, Levy, Marina, Lillibridge, John, Liu, Jianqiang, Llovel, William, Lyard, Florent, Macintosh, Claire, Makhoul Varona, Eduard, Manfredi, Cécile, Marin, Frédéric, Mason, Evan, Massari, Christian, Mavrocordatos, Constantin, Maximenko, Nikolai, McMillan, Malcolm, Medina, Thierry, Melet, Angelique, Meloni, Marco, Mertikas, Stelios, Metref, Sammy, Meyssignac, Benoit, Minster, Jean-François, Moreau, Thomas, Moreira, Daniel, Morel, Yves, Morrow, Rosemary, Moyard, John, Mulet, Sandrine, Naeije, Marc, Nerem, Robert Steven, Ngodock, Hans, Nielsen, Karina, Nilsen, Jan Even Øie, Niño, Fernando, Nogueira Loddo, Carolina, Noûs, Camille, Obligis, Estelle, Otosaka, Inès, Otten, Michiel, Oztunali Ozbahceci, Berguzar, P. Raj, Roshin, Paiva, Rodrigo, Paniagua, Guillermina, Paolo, Fernando, Paris, Adrien, Pascual, Ananda, Passaro, Marcello, Paul, Stephan, Pavelsky, Tamlin, Pearson, Christopher, Penduff, Thierry, Peng, Fukai, Perosanz, Felix, Picot, Nicolas, Piras, Fanny, Poggiali, Valerio, Poirier, Étienne, Ponce de León, Sonia, Prants, Sergey, Prigent, Catherine, Provost, Christine, Pujol, M-Isabelle, Qiu, Bo, Quilfen, Yves, Rami, Ali, Raney, R. Keith, Raynal, Matthias, Remy, Elisabeth, Rémy, Frédérique, Restano, Marco, Richardson, Annie, Richardson, Donald, Ricker, Robert, Ricko, Martina, Rinne, Eero, Rose, Stine Kildegaard, Rosmorduc, Vinca, Rudenko, Sergei, Ruiz, Simón, Ryan, Barbara J., Salaün, Corinne, Sanchez-Roman, Antonio, Sandberg Sørensen, Louise, Sandwell, David, Saraceno, Martin, Scagliola, Michele, Schaeffer, Philippe, Scharffenberg, Martin G., Scharroo, Remko, Schiller, Andreas, Schneider, Raphael, Schwatke, Christian, Scozzari, Andrea, Ser-giacomi, Enrico, Seyler, Frederique, Shah, Rashmi, Sharma, Rashmi, Shaw, Andrew, Shepherd, Andrew, Shriver, Jay, Shum, C.K., Simons, Wim, Simonsen, Sebatian B., Slater, Thomas, Smith, Walter, Soares, Saulo, Sokolovskiy, Mikhail, Soudarin, Laurent, Spatar, Ciprian, Speich, Sabrina, Srinivasan, Margaret, Srokosz, Meric, Stanev, Emil, Staneva, Joanna, Steunou, Nathalie, Stroeve, Julienne, Su, Bob, Sulistioadi, Yohanes Budi, Swain, Debadatta, Sylvestre-baron, Annick, Taburet, Nicolas, Tailleux, Rémi, Takayama, Katsumi, Tapley, Byron, Tarpanelli, Angelica, Tavernier, Gilles, Testut, Laurent, Thakur, Praveen K., Thibaut, Pierre, Thompson, LuAnne, Tintoré, Joaquín, Tison, Céline, Tourain, Cédric, Tournadre, Jean, Townsend, Bill, Tran, Ngan, Trilles, Sébastien, Tsamados, Michel, Tseng, Kuo-Hsin, Ubelmann, Clément, Uebbing, Bernd, Vergara, Oscar, Verron, Jacques, Vieira, Telmo, Vignudelli, Stefano, Vinogradova Shiffer, Nadya, Visser, Pieter, Vivier, Frederic, Volkov, Denis, von Schuckmann, Karina, Vuglinskii, Valerii, Vuilleumier, Pierrik, Walter, Blake, Wang, Jida, Wang, Chao, Watson, Christopher, Wilkin, John, Willis, Josh, Wilson, Hilary, Woodworth, Philip, Yang, Kehan, Yao, Fangfang, Zaharia, Raymond, Zakharova, Elena, Zaron, Edward D., Zhang, Yongsheng, Zhao, Zhongxiang, Zinchenko, Vadim, and Zlotnicki, Victor

Published
2021
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2. The SARAL/AltiKa mission: A step forward to the future of altimetry

Author

Verron, Jacques, Bonnefond, Pascal, Andersen, Ole, Ardhuin, Fabrice, Bergé-Nguyen, Muriel, Bhowmick, Suchandra, Blumstein, Denis, Boy, François, Brodeau, Laurent, Crétaux, Jean-François, Dabat, Mei Ling, Dibarboure, Gérald, Fleury, Sara, Garnier, Florent, Gourdeau, Lionel, Marks, Karen, Queruel, Nadège, Sandwell, David, Smith, Walter H.F., and Zaron, E.D.

Published
2021
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3. Internal-tide vertical structure and steric sea surface height signature south of New Caledonia revealed by glider observations.

Author

Bendinger, Arne, Cravatte, Sophie, Gourdeau, Lionel, Rainville, Luc, Vic, Clément, Sérazin, Guillaume, Durand, Fabien, Marin, Frédéric, and Fuda, Jean-Luc

Subjects
VERTICAL integration, UNDERWATER gliders, GLIDERS (Aeronautics), MODEL airplanes, TIDAL forces (Mechanics)
Abstract

In this study, we exploit autonomous underwater glider data to infer internal-tide dynamics south of New Caledonia, an internal-tide-generation hot spot in the southwestern tropical Pacific. By fitting a sinusoidal function to vertical displacements at each depth using a least-squares method, we simultaneously estimate diurnal and semidiurnal tides. Our analysis reveals regions of enhanced tidal activity, strongly dominated by the semidiurnal tide. To validate our findings, we compare the glider observations to a regional numerical simulation that includes tidal forcing. This comparison assesses the simulation's realism in representing tidal dynamics and evaluates the glider's ability to infer internal-tide signals and their signature in sea surface height (SSH). The glider observations and a pseudo glider, simulated using hourly numerical model output with identical sampling, exhibit similar amplitude and phase characteristics along the glider track. Existing discrepancies are in large part explained by tidal incoherence induced by eddy–internal-tide interactions. We infer the semidiurnal internal-tide signature in steric SSH by the integration of vertical displacements. Within the upper 1000 m, the pseudo glider captures roughly 78 % of the steric SSH total variance explained by the full water column signal. This value increases to over 90 % when projecting the pseudo glider's vertical displacements onto climatological baroclinic modes and extrapolating to full depth. Notably, the steric SSH from glider observations aligns closely with empirical estimates derived from satellite altimetry, highlighting the internal tide's predominant coherent nature during the glider's sampling. [ABSTRACT FROM AUTHOR]

Published
2024
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7. Regional modeling of internal-tide dynamics around New Caledonia – Part 1: Coherent internal-tide characteristics and sea surface height signature

Author

Bendinger, Arne, Cravatte, Sophie, Gourdeau, Lionel, Brodeau, Laurent, Albert, Aurélie, Tchilibou, Michel, Lyard, Florent, Vic, Clement, Bendinger, Arne, Cravatte, Sophie, Gourdeau, Lionel, Brodeau, Laurent, Albert, Aurélie, Tchilibou, Michel, Lyard, Florent, and Vic, Clement

Abstract

The southwestern tropical Pacific exhibits a complex bathymetry and represents a hot spot of internal-tide generation. Based on a tailored high-resolution regional model, we investigate for the first time the internal-tide field around the New Caledonia islands through energy budgets that quantify the coherent internal-tide generation, propagation, and dissipation. A total of 15.27 GW is converted from the barotropic to the baroclinic M2 tide with the main conversion sites associated with the most prominent bathymetric structures such as continental slopes and narrow passages in the north (2.17 GW) and ridges and seamounts south of New Caledonia (3.92 GW). The bulk of baroclinic energy is generated in shallow waters around 500 m depth and on critical to supercritical slopes, highlighting the limitations of linear semi-analytical models in those areas. Despite the strongly dominant mode-1 generation, more than 50 % of the locally generated energy either dissipates in the near field close to the generation sites or loses coherence. The remaining baroclinic energy propagates within well-defined tidal beams with baroclinic energy fluxes of up to 30 kW m−1 toward the open ocean. The New Caledonia site represents a challenge for SWOT (Surface Water and Ocean Topography) observability of balanced motion in the presence of internal tides with sea surface height (SSH) signatures >6 cm at similar wavelengths. We show for our study region that a correction of SSH for the coherent internal tide potentially increases the observability of balanced motion from wavelengths >160 km to well below 100 km.

Published
2023
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8. Regional modeling of internal tide dynamics around New Caledonia: energetics and sea surface height signature.

Author

Bendinger, Arne, Cravatte, Sophie, Gourdeau, Lionel, Brodeau, Laurent, Albert, Aurélie, Tchilibou, Michel, Lyard, Florent, and Vic, Clément

Subjects
OCEAN surface topography, CONTINENTAL slopes, MESOSCALE eddies, ENERGY budget (Geophysics), WATER depth, TIDES, SEAMOUNTS
Abstract

The Southwestern Tropical Pacific exhibits a complex bathymetry and represents a hot spot of internal tide generation. Based on a tailored high-resolution regional model, we investigate for the first time the internal tide field around the New Caledonia islands through energy budgets that quantify the internal tide generation, propagation, and dissipation. A total of 15.97 GW is converted from the barotropic to the baroclinic tide with the main conversion sites associated with the most prominent bathymetric structures such as continental slopes and narrow passages in the north (2.17 GW) and ridges and seamounts south of New Caledonia (3.92 GW). The bulk of baroclinic energy is generated in shallow waters around 500 m depth and on critical to supercritical slopes highlighting the limitations of linear semi-analytical models in those areas. Despite the strongly dominant mode-1 generation, more than 50 % of the locally generated energy dissipates in the near-field close to the generation sites. The remaining energy propagates within well-defined tidal beams with baroclinic energy fluxes of up to 30 kW m-1 toward the open ocean, strongly dominated by mode-1. The energetic mesoscale eddy activity in the region appears to be the main source of tidal incoherence. Locally, mesoscale eddy-driven stratification changes induce variations of the conversion term. In the far-field, incoherence of the energy flux arises through the interaction of the tidal beam with the eddying background flow. The New Caledonia site represents a challenge for SWOT (Surface Water Ocean Topography) observability of meso- and submesoscale dynamics in the presence of internal tides with sea surface height signatures > 6 cm. We show that a correction of the coherent baroclinic tide may improve the observability range by shifting the transition scale between balanced and unbalanced flow in winter from 180 km to 50-80 km. In contrast, in summer observability increases only marginally due to the seasonally amplified signature of the incoherent tide at scales below 100 km. [ABSTRACT FROM AUTHOR]

Published
2023
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9. What is the benefit of high-resolution sea level anomaly datasets? A case study in the Bay of Biscay and New Caledonia regions based on Jason2-3, Saral/AltiKA and Sentinel3

Author

Gourdeau, Lionel, Ayoub, Nadia, Morrow, Rosemary, Chevrier, Robin, Dabat, MeiLing, Leger, Fabien, and Blarel, Fabien

Abstract

Wavelength spectral analysis of alongtrack altimetric data helps to characterize the seasonal and spatial variability of the sea level anomaly (SLA) signal. It allows us to infer the nature of the surface dynamics (balanced vs unbalanced motion, internal waves). For such analyses, low resolution mode data sets (1 Hz, 6-7 km sampling) are classically used. At this stage there is a strong gap in terms of effective resolution between the 1 Hz along track products (40-70 km resolution) and what is expected from the data of the future SWOT mission. However, the finest spatial sampling is 20 Hz for Jason, and 40 Hz for SARAL/AltiKa. For these products, the main limitation to observe small mesoscale is the existence of a spectral “hump” and a larger noise level due to surface waves and other surface inhomogeneities within the radar footprint. The new concept of SAR mode altimeter as used in Sentinel 3 provides better precision and resolution capabilities. In the prospect of the SWOT mission, this paper focuses on high resolution (HR) datasets from the recent satellite missions based on regional analysis including Jason-2/3, SARAL/AltiKa, and Sentinel-3. At the present time, there is no HR-SLA datasets for all these missions and over the global ocean that are easily usable. In this poster we review different methods and options in the data processing to get HR-SLA. The ability of the different datasets and processing to provide information on the dynamics is illustrated in two contrasted regions: the Bay of Biscay located in the mid-latitudes NE Atlantic and the subtropical region south of New Caledonia in the tropics. The benefit of HR data is evident for scales up to 100 km. It illustrates both the gain brought by the Ka-band of Saral and the SAR mode of S3A over the Ku band of Jason and the benefit of the long time series of Jason data for the studies of internal tides. We emphasize the need to take into account the anisotropy and the very local nature of the ocean dynamics properties in order to assess regional dynamics.

Published
2022
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18. Comparison of the altimetric signal with in situ measurements in the tropical Atlantic Ocean

Author

Arnault, Sabine, Gourdeau, Lionel, and Menard, Yves

Subjects
South Atlantic Ocean -- Environmental aspects, Artificial satellites in surveying -- Usage, Hydrographic surveying -- Usage, Earth sciences
Abstract

Radar altimetry data was taken by the GEOSAT at the same period that the ARAMIS 1 experiment collected in situ data from aboard a merchant ship along a track in the tropical Atlantic Ocean. Comparison of the two data sets showed good agreement between altimetric and in situ measurements, except in the southern part of the track. Some possible explanations regarding possible sources of discrepancies are given.

Published
1992

21. Zonal and Meridional Mass Redistribution in the Tropical Pacific During El Nino Southern Oscillation Events

Author

Delcroix, Thierry, Gourdeau, Lionel, Rual, Pierre, and Murtugudde, Raghuram

Subjects
Oceanography
Abstract

This note aims at documenting the ENSO-related sea level changes for the whole tropical Pacific, and for the 1979-1996 period which covers numerous El Nino and La Nina events. For this purpose, we rely on (a) 0/450 dbar surface dynamic height anomaly (an alias for sea level) derived from XBT and TOGA-TAO measurements during 1979-1996, (b) TOPEX/Poseidon derived sea level anomaly during 1993-1996, and (c) Murtugudde et al. [1996] model sea level output during 1979-1995.

Published
1997

22. Observed Characteristics and Vertical Structure of Mesoscale Eddies in the Southwest Tropical Pacific

Author

Keppler, Lydia, Cravatte, Sophie, Chaigneau, Alexis, Pegliasco, Cori, Gourdeau, Lionel, Singh, Awnesh, Keppler, Lydia, Cravatte, Sophie, Chaigneau, Alexis, Pegliasco, Cori, Gourdeau, Lionel, and Singh, Awnesh

Abstract

In the Southwest Pacific Ocean, waters transit from the subtropical gyre before being redistributed equatorward and poleward. While the mean pathways are known, the contribution to the mixing and transport of the water from mesoscale eddies has not been comprehensively investigated. In this research, satellite altimetry data, combined with an eddy detection and tracking algorithm is used to investigate the distribution and surface characteristics of mesoscale eddies in this region of complex bathymetry (10 degrees S-30 degrees S, 140 degrees E-190 degrees E). Detected eddies are then colocalized with in situ data from Argo floats to determine their vertical structure and the effect of eddies on the water masses. The numerous islands affect the eddy behavior as most eddies are formed in the lee of islands, propagate westward and decay when encountering shallow bathymetry. Eddies are sparse and short-lived in the tropical area north of Fiji, impacting only the top 200 meters of water. They do not appear to be able to trap and transport waters in this region. In the Coral Sea, a region of lateral shear between currents transporting waters of different origins, eddies are more numerous and energetic. They affect the water properties down to at least 500 m depth, and anticyclonic eddies trap water to approximate to 200 m, contributing to the upper thermocline waters mixing and transport. South of New Caledonia, mesoscale eddies are ubiquitous, with typical lifetimes longer than 5 months. They affect the temperature, salinity, and velocities down to approximate to 1,000 m depth, and weakly contribute to the mixing of lower thermocline waters.

Published
2018
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30. Internal tides in the Solomon Sea in contrasted ENSO conditions.

Author

Tchilibou, Michel, Gourdeau, Lionel, Lyard, Florent, Morrow, Rosemary, Larrouy, Ariane Koch, Allain, Damien, and Djath, Bughsin

Subjects
TIDES, EL Nino, LA Nina, WATER masses, THERMOCLINES (Oceanography), SEAS, SOUTHERN oscillation
Abstract

The Solomon Sea is a place of intense Low Latitudes Western Boundary current transiting to the equator where mesoscale activity is superimposed on internal tides. In this marginal sea, the cumulated effects of these dynamical constraints result in water mass transformation as observed by in situ observations. The objective of this paper is to document the M2 internal tides in the Solomon Sea and their impacts based on two regional simulations with and without tides. Because the Solomon Sea is under the influence of ENSO, the characteristics of the internal tides are analyzed for two contrasted ENSO conditions: the 1997-1998 El Niño and the 1999 La Niña. The generation, propagation and dissipation of the internal tides are sensitive to changes in stratification and mesoscale activity between El Niño and La Niña. Mode 1 is the dominant mode to propagate baroclinic tidal energy within the Solomon Sea, but the El Niño conditions, with stratification closer to the surface, are favorable for the propagation of mode 2. The la Niña case with a high level of mesoscale activity favors the appearance of incoherent internal tides. These results illustrate the complexity in predicting internal tides in order to access meso and submesoscale signatures from altimetric missions, including the future SWOT mission. Diapycnal mixing induced by the internal tides is efficient in eroding the salinity maximum of the upper thermocline water, and in cooling the surface temperature interacting with the atmosphere. Such effects are particularly visible far from the strong currents, where particles may experience the tidal effects during a longer time. Nevertheless, the impacts are different when considering particular ENSO conditions. The interaction of internal tides with the surface mesoscale activity reduces surface cooling during El Niño 1998, but increases surface warming during La Niña 1999, with possible impacts on regional air sea interaction. [ABSTRACT FROM AUTHOR]

Published
2019
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31. Multiscale dynamical analysis of a high-resolution numerical model simulation of the Solomon Sea circulation

Author

Djath, B., Verron, J., Melet, A., Gourdeau, Lionel, Barnier, B., and Molines, J. M.

Subjects
numerical simulation, Solomon Sea, oceanography
Abstract

A high 1/36 degrees resolution numerical model is used to study the ocean circulation in the Solomon Sea. An evaluation of the model with (the few) available observation shows that the 1/36 degrees resolution model realistically simulates the Solomon Sea circulations. The model notably reproduces the high levels of mesoscale eddy activity observed in the Solomon Sea. With regard to previous simulations at 1/12 degrees resolution, the average eddy kinetic energy levels are increased by up to approximate to 30-40% in the present 1/36 degrees simulation, and the enhancement extends at depth. At the surface, the eddy kinetic energy level is maximum in March-April-May and is minimum in December-January-February. The high subsurface variability is related to the variability of the western boundary current (New Guinea Coastal Undercurrent). Moreover, the emergence of submesoscales is clearly apparent in the present simulations. A spectral analysis is conducted in order to evidence and characterize the modeled submesoscale dynamics and to provide a spectral view of scales interactions. The corresponding spectral slopes show a strong consistency with the Surface Quasi-Geostrophic turbulence theory.

Published
2014

32. The Southwest Pacific Ocean circulation and climate experiment (SPICE) : report to CLIVAR SSG

Author

Ganachaud, Alexandre, Cravatte, Sophie, Melet, A., Schiller, A., Holbrook, N.J., Sloyan, B.M., Widlansky, M.J., Bowen, M., Verron, J., Wiles, P., Ridgway, K., Sutton, P., Sprintall, J., Steinberg, C., Brassington, G., Cai, W., Davis, R., Gasparin, F., Gourdeau, Lionel, Hasegawa, T., Kessler, W., Maes, Christophe, Takahashi, K., Richards, K.J., and Send, U.

Published
2014

33. Rapport de la mission SECARGO à bord du navire océanographique Alis : 7-18 mai 2010 ; mer des îles Loyauté, océan Pacifique sud-ouest

Author

Maes, Christophe, Gasparin, Florent, Eldin, Gérard, Rodier, Martine, Varillon, David, Ganachaud, Alexandre, Marin, Frédéric, and Gourdeau, Lionel

Subjects
CAMPAGNE OCEANOGRAPHIQUE, SALINITE, OXYGENE DISSOUS, TEMPERATURE, STATION HYDROLOGIQUE
Abstract

La campagne SECARGO représente une composante de la collecte d'observations in situ intégrée dans le cadre du projet scientifique SPICE (Southwest Pacific Ocean Circulation and Climate Experiment) soutenu par les instances internationales des programmes sur l'étude du climat et de sa variabilité, CLIVAR et WCRP, et par le volet scientifique du projet d'océanographie opérationnelle française, le Groupe Mission MERCATOR-CORIOLIS (GMMC). Le contexte scientifique de SECARGO repose sur deux thèmes principaux du projet SPICE d'étude dans le Pacifique sud-ouest : a) l'étude de " l'inflow " des eaux de la thermocline en mer de Corail et b) l'étude des caractéristiques hydrologiques de la mer de Corail et de la mer des Salomon. L'objectif principal de cette campagne en mer portait sur l'observation du Jet Nord Calédonien au nord du récif D'Entrecasteaux (15°-18°S ; 162°- 165°E) et dans la région entre la Nouvelle Calédonie et l'archipel du Vanuatu. L'étude des caractéristiques hydrologiques de ces eaux dans la colonne d'eau de 0 à 2000 m de profondeur représente le second volet d'intérêt principal. Cette campagne a eu lieu dans cette région de l'Océan Pacifique sud-ouest du 7 au 18 mai 2010 à bord du Navire Océanographique L'Alis de l'Institut de Recherche pour le Développement (IRD). Au cours de la campagne SECARGO, 70 stations hydrologiques comprenant un profil de température, de salinité et de la concentration en oxygène dissous avec une sonde CTD-O2 ont été effectuées. En parallèle, des prélèvements discrets à partir de bouteilles Niskin ont été réalisés pour les analyses de la salinité et de la concentration en oxygène dissous. Des mesures de courants horizontaux (0-250 m) en continu ont été enregistrées à partir du courantomètre ADCP monté sur la coque du navire. La température et la salinité proche de la surface ont été enregistrées à partir d'un thermo-salinographe (TSG) toutes les minutes. Des flotteurs autonomes du réseau Argo et des bouées dérivantes de surface équipées de capteur de conductivité pour la mesure de surface de la salinité dans le cadre des calibrations des observations de la mission satellite SMOS (Soil Moisture Ocean Salinity) de l'ESA (European Spatial Agency) ont été largués lors de cette campagne en mer. Ce rapport décrit le déroulement de la campagne ainsi que le matériel utilisé et les méthodes de calibration.

Published
2014

34. Advances from the southwest Pacific Ocean circulation and climate experiment (SPICE)

Author

Ganachaud, Alexandre, Bowen, M., Brassington, G., Cai, W., Cravatte, Sophie, Davis, R., Gourdeau, Lionel, Hasegawa, T., Hill, K., Holbrook, N., Kessler, W., Maes, Christophe, Melet, A., Qiu, B., Ridgway, K., Roemmich, D., Schiller, A., Send, U., Sloyan, B., Sprintall, J., Steinberg, C., Sutton, P., Verron, J., Widlansky, M., and Wiles, P.

Subjects
CIRCULATION OCEANIQUE, ZONE DE CONVERGENCE INTERTROPICALE, THERMOCLINE, PROGRAMME DE RECHERCHE, CLIMATOLOGIE
Published
2013

35. Spectral signatures of the tropical Pacific dynamics from model and altimetry: A focus on the meso/submesoscale range.

Author

Tchilibou, Michel, Gourdeau, Lionel, Morrow, Rosemary, Serazin, Guillaume, Djath, Bughsin, and Lyard, Florent

Subjects
OCEAN dynamics, ALTIMETRY, WAVELENGTHS
Abstract

The processes that contribute to the flat Sea Surface Height (SSH) wavenumber spectral slopes observed in the tropics by satellite altimetry are examined in the tropical Pacific. The tropical dynamics are first investigated with a 1/12° global model. The equatorial region from 10° N-10° S is dominated by Tropical Instability Waves with a peak of energy at 1000 km wavelength, strong anisotropy, and a cascade of energy from 600 km down to smaller scales. The off-equatorial regions from 10-20° latitude are characterized by a narrower mesoscale range, typical of mid latitudes. In the tropics, the spectral taper window and segment lengths need to be adjusted to include these larger energetic scales. The equatorial and off-equatorial regions of the 1/12° model have surface kinetic energy spectra consistent with quasi-geostrophic turbulence. The balanced component of the dynamics slightly flatten the EKE spectra, but modeled SSH wavenumber spectra maintain a steep slope that does not match the observed altimetric spectra. A second analysis is based on 1/36° high-frequency regional simulations in the western tropical Pacific, with and without explicit tides, where we find a strong signature of internal waves and internal tides that act to increase the smaller-scale SSH spectral energy power and flattening the SSH wavenumber spectra, in agreement with the altimetric spectra. The coherent M2 baroclinic tide is the dominant signal at ~ 140 km wavelength. At short scales, wavenumber SSH spectra are dominated by incoherent internal tides and internal waves which extend up to 200 km in wavelength. These incoherent internal waves impact on space scales observed by today's alongtrack altimetric SSH, and also on the future SWOT 2D swath observations, raising the question of altimetric observability of the shorter mesoscale structures in the tropics. [ABSTRACT FROM AUTHOR]

Published
2018
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37. Solomon Sea water masses pathways to the Equator and their transformations

Author

Mélet, Angélique, Verron, Jacques, Gourdeau, Lionel, Koch-Larrouy, Ariane, Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), 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), SPICE/CLIVAR, and Solwara

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere
Abstract

International audience; The Solomon Sea is a key region of the southwest Pacific Ocean, connecting the thermocline subtropics to the equator via western boundary currents (WBCs). Modifications to water masses are thought to occur in this region because of the significant mixing induced by internal tides, eddies, and the WBCs. Despite their potential influence on the equatorial Pacific thermocline temperature and salinity and their related impact on the low-frequency modulation of El Nin˜ o-Southern Oscillation, modifications to water masses in the Solomon Sea have never been analyzed to our knowledge. A high-resolution model incorporating a tidal mixing parameterization was implemented to depict and analyze water mass modifications and the Solomon Sea pathways to the equator in a Lagrangian quantitative framework. The main routes from the Solomon Sea to the equatorial Pacific occur through the Vitiaz and Solomon straits, in the thermocline and intermediate layers, and mainly originate from the Solomon Sea south inflow and from the Solomon Strait itself. Water mass modifications in the model are characterized by a reduction of the vertical temperature and salinity gradients over the water column: the high salinity of upper thermocline water [Subtropical Mode Water (STMW)] is eroded and exported toward surface and deeper layers, whereas a downward heat transfer occurs over the water column. Consequently, the thermocline water temperature is cooled by 0.15°-0.3°C from the Solomon Sea inflows to the equatorward outflows. This temperature modification could weaken the STMW anomalies advected by the subtropical cell and thereby diminish the potential influence of these anomalies on the tropical climate. The Solomon Sea water mass modifications can be partially explained (~60%) by strong diapycnal mixing in the Solomon Sea. As for STMW, about a third of this mixing is due to tidal mixing.

Published
2011

38. Variability of the surface and thermocline circulations in the Solomon Sea

Author

Mélet, Angélique, Verron, Jacques, Gourdeau, Lionel, Kessler, William, Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), 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), NOAA Pacific Marine Environmental Laboratory [Seattle] (PMEL), and National Oceanic and Atmospheric Administration (NOAA)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere
Abstract

International audience; In the southwest tropical Pacific, subtropical waters from the SEC flow in the Solomon Sea, mainly through the western boundary New Guinea Coastal Undercurrent (NGCU), before joining the equatorial western Pacific by three narrow straits. Because the NGCU is a primary source of the EUC, variations of its characteristics are expected to play a role in the equatorial thermocline features and more generally on decadal climate variability. Moreover, the highest levels in sea level variability in the entire South Tropical Pacific Ocean are found in the Solomon Sea region. Therefore, the study of the poorly known Solomon Sea is a key issue from a climate perspective (e.g. SPICE/CLIVAR program). In this study, we consider the circulation in the Solomon Sea and its variability through both modeling and altimetric data analysis. Since the geography of the region is extremely intricate, a high-resolution (1/12°) model with a realistic bathymetry has been implemented based on the NEMO code, and specifically retreated Topex-Poseidon along-track sea level data were used in addition to standard gridded altimetric data. We will first describe the fine-scale mean thermocline circulation based on our numerical simulation. It involves a complex system of western boundary currents (WBC). Transport limitation through Vitiaz Strait is responsible for a splitting of the NGCU in two branches. The main branch flows through Vitiaz Strait and along the New Guinea coast. The other branch , denoted as the New Britain Coastal Undercurrent, flows along the south coast of New Britain. The NBCU mainly flow through Solomon Strait and join the New Ireland Coastal Undercurrent, providing the most direct western boundary-equator connection. At annual time scales, the Solomon Sea thermocline WBC variability results from the combination of equatorial dynamics, of remotely forced Rossby waves north of 10°S and of the spinup and -down of the subtropical gyre as a response to Rossby waves forced south of 10°S. Altimetric along-track data appear especially helpful for documenting the observed fine structure of the surface coastal currents. The annual variability of the WBC that emerged from altimetry compared quite well with the variability described earlier at thermocline level in our model. At interannual time scales, the modeled NGCU thermocline transport variability is related to ENSO : it strenghens during El Nino and weakens during La Nina events. The transport anomalies are mainly transmitted to the NBCU and through Solomon Strait than through Vitiaz Strait. An analysis of altimetric data show that WBC surface transport anomalies counterbalance changes in western Equatorial Pacific warm water volume, confirming the phasing of South Pacific WBC to ENSO.

Published
2010

39. The LLWBCs of the Solomon Sea depicted by altimetry and gliders

Author

Gourdeau, Lionel, Mélet, Angélique, Verron, Jacques, Kessler, William, Dussurget, Renaud, Davis, Russ E., 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), Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), NOAA Pacific Marine Environmental Laboratory [Seattle] (PMEL), National Oceanic and Atmospheric Administration (NOAA), Physical Oceanography Research Division [La Jolla], Scripps Institution of Oceanography (SIO), University of California [San Diego] (UC San Diego), University of California-University of California-University of California [San Diego] (UC San Diego), and University of California-University of California

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere
Published
2010

40. The low latitude western boundary currents of the Solomon Sea depicted by altimetry

Author

Gourdeau, Lionel, Mélet, Angélique, Kessler, William, Dussurget, Renaud, Davis, Russ E., 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), Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), NOAA Pacific Marine Environmental Laboratory [Seattle] (PMEL), National Oceanic and Atmospheric Administration (NOAA), Physical Oceanography Research Division [La Jolla], Scripps Institution of Oceanography (SIO), University of California [San Diego] (UC San Diego), University of California-University of California-University of California [San Diego] (UC San Diego), and University of California-University of California

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere
Published
2010

41. On the role of the Solomon Sea on ENSO modulation: a preliminary modeling study

Author

Mélet, Angélique, Verron, Jacques, Gourdeau, Lionel, Kessler, William, Koch-Larrouy, Ariane, Brankart, Jean-Michel, Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), 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), NOAA Pacific Marine Environmental Laboratory [Seattle] (PMEL), and National Oceanic and Atmospheric Administration (NOAA)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere
Abstract

The Pacific decadal variability, such as the low-frequency modulation of El Niño Southern Oscillation, has been hypothesized to be influenced by changes in the strength or water mass properties of the meridional circulation associated with the subtropical cells (STC). The STCs provide a connection between subtropical waters and the equatorial Pacific at thermocline level, by both an interior pathway and by the low latitude boundary currents. The LLWBC branch of the South Pacific STC has been pointed as the main source of the Equatorial Undercurrent and of the Equatorial Cold Tongue by both observational and modeling studies. Those currents transit in the poorly documented Solomon Sea, located in the western boundary of the tropical South Pacific. The very intricate bathymetry of the semi-enclosed Solomon Sea complexifies the STC pathways to the equator. In this study, we characterize the fine-scale thermocline mean circulation in the Solomon Sea. As available observations of the region are sparse, our approach is based on modeling. High-resolution is required to realistically represent the complex topography. It is achieved through the implementation of a hierarchy of Ocean General Circulation Models (OGCMs) : a 1/12° resolution model of the Solomon Sea is interactively into a ¼° regional model of the southwest Pacific, itself embedded through open boundary conditions in a global 1/4° OGCM. We show that the circulation involves an inflow from the southern open Solomon Sea which is distributed via WBCs between the three narrow straits that connect this region to the equatorial Pacific. The system of WBCs appears to be complex, and provides connection of subtropical water to the EUC at different longitudes, which may be associated to different climate impacts. Early experiments of data assimilation are performed to assess the ability of localised 3-D glider (underwater vehicle) and synoptic altimetric sea level anomalies observations to control the main Solomon Sea WBC. An observing system simulation experiments (OSSE) strategy is implemented and data assimilation is performed in our multigrid model through a local reduced order analysis, based on a sequential scheme derived from the SEEK filter. Water mass transformations are characterized in our high-resolution model in a lagrangian quantitative framework. We show that strong diapycnal mixing, partly due to internal tide waves dissipation, is responsible for a reduction of the temperature and salinity vertical gradients. More specifically, diapycnal mixing erodes the high salinities associated with the waters of subtropical origin carried by the STC, and this erosion is associated to a downward heat transfer. Therefore, the Solomon Sea might damp the spiciness anomalies formed in the southeast Pacific and advected equatorward to the EUC by the LLWBC branch of the South Pacific STC, with reduced impact of the STC on the Tropical Pacific climate variability.

Published
2010

43. Variability of the Solomon Sea from altimetry sea level data

Author

Mélet, Angélique, Gourdeau, Lionel, Verron, Jacques, Kessler, William, Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), 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), NOAA Pacific Marine Environmental Laboratory [Seattle] (PMEL), and National Oceanic and Atmospheric Administration (NOAA)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere
Published
2008

44. Transport anomalies through the Solomon Sea and their relation with Warm Water Volume in the western equatorial Pacific at the ENSO time-scale: an altimetric study

Author

Gourdeau, Lionel, Mélet, Angélique, Kessler, William, Maes, Christophe, 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), Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), NOAA Pacific Marine Environmental Laboratory [Seattle] (PMEL), and National Oceanic and Atmospheric Administration (NOAA)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere
Published
2008

45. Variability of the Circulation in the Solomon sea From High Resolution Modelling and Altimetry

Author

Mélet, Angélique, Molines, Jean-Marc, Gourdeau, Lionel, Verron, Jacques, Ganachaud, Alexandre, Maes, Christophe, Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), 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), and 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)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere
Published
2008

46. The Southwest Pacific Ocean circulation and climate experiment (SPICE): a new CLIVAR programme

Author

Ganachaud, Alexandre, Kessler, W., Brassington, G., Mechoso, C.R., Wijffels, S., Ridgway, K., Cai, W., Holbrook, N., Sutton, P., Bowen, M., Qiu, B., Timmermann, A., Roemmich, D., Sprintall, J., Neelin, D., Lintner, B., Diamond, H., Cravatte, Sophie, Gourdeau, Lionel, Eastwood, P., and Aung, T.

Subjects
MODELE, CIRCULATION OCEANIQUE, CLIMAT, COURANT MARIN, ZONE DE CONVERGENCE TROPICALE, INTERACTION OCEAN ATMOSPHERE
Published
2008

48. Southwest Pacific Ocean circulation and climate experiment (SPICE). Part 1. Scientific background

Author

Ganachaud, Alexandre, Kessler, W., Wijffels, S., Ridgway, K., Cai, W., Holbrook, N., Bowen, M., Sutton, P., Qiu, B., Timmermann, A., Roemmich, D., Sprintall, J., Cravatte, Sophie, Gourdeau, Lionel, and Aung, T.

Subjects
CIRCULATION OCEANIQUE, THERMOCLINE, COURANT MARIN, ZONE DE CONVERGENCE TROPICALE, INTERACTION OCEAN ATMOSPHERE, FLUX THERMIQUE, IMPACT SUR L'ENVIRONNEMENT
Published
2007

49. GRACE : an improved MDT reference for altimeter data assimilation

Author

Castruccio, Frédéric, Verron, Jacques, Gourdeau, Lionel, Brankart, Jean-Michel, Brasseur, Pierre, Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), 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), and 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)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph]
Abstract

Recent advances in our knowledge of the earth geoid have made it possible to exploit absolute sea surface height measurements in realistic numerical modelling studies of the ocean. This letter provides evidence of the benefit of the GRACE referenced mean dynamic topography (MDT) for the simulation of the tropical Pacific ocean through the joint assimilation of altimetric data and of vertical temperature profiles from the TAO/TRITON array. Results are considered in relation to those obtained using a classical model MDT, based on the model itself, and are validated against independent XBT data. The use of the GRACE MDT leads to significantly improved results with respect to these independent data. If the compatibility between the altimetric sea surface height and the TAO/TRITON temperature improves the model simulation, some limitations exist, especially in the Warm Pool where a part of the sea surface height signature is associated to a salinity signal.

Published
2007

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