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45 results on '"Garçon, Veronique"'

1. System controls of coastal and open ocean oxygen depletion

Author

Pitcher, Grant C., Aguirre-Velarde, Arturo, Breitburg, Denise, Cardich, Jorge, Carstensen, Jacob, Conley, Daniel J., Dewitte, Boris, Engel, Anja, Espinoza-Morriberón, Dante, Flores, Georgina, Garçon, Véronique, Graco, Michelle, Grégoire, Marilaure, Gutiérrez, Dimitri, Hernandez-Ayon, José Martin, Huang, Huai-Hsuan May, Isensee, Kirsten, Jacinto, María Elena, Levin, Lisa, Lorenzo, Alberto, Machu, Eric, Merma, Lander, Montes, Ivonne, SWA, Naqvi, Paulmier, Aurelien, Roman, Michael, Rose, Kenneth, Hood, Raleigh, Rabalais, Nancy N., Salvanes, Anne Gro V., Salvatteci, Renato, Sánchez, Sonia, Sifeddine, Abdelfettah, Tall, Abdoul Wahab, Plas, Anja K. van der, Yasuhara, Moriaki, Zhang, Jing, and Zhu, ZY

Published
2021
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2. Biogeochemistry of greenhouse gases in coastal upwelling systems: Processes and sensitivity to global change

Author

Lachkar, Zouhair, Cornejo-D'Ottone, Marcela, Singh, Arvind, Arístegui, Javier, Dewitte, Boris, Fawcett, Sarah, Garçon, Veronique, Lovecchio, Elisa, Molina, Veronica, Vinayachandran, P. N. M., Lachkar, Zouhair, Cornejo-D'Ottone, Marcela, Singh, Arvind, Arístegui, Javier, Dewitte, Boris, Fawcett, Sarah, Garçon, Veronique, Lovecchio, Elisa, Molina, Veronica, and Vinayachandran, P. N. M.

Abstract

Major coastal upwelling systems are among the most productive marine ecosystems in the world. They contribute disproportionately to the cycling of carbon and nutrients in the ocean and influence marine biogeochemistry beyond their productive regions. Characterized by intense microbial respiration (both aerobic and anaerobic), major coastal upwelling systems are also hotspots for the production and outgassing of potent greenhouse gases (GHG) such as CO2, N2O, and CH4. Quantifying and understanding these roles in the context of a changing climate is therefore a subject of great interest. Here we provide a short synthesis of the current knowledge of the contributions of major coastal upwelling systems to the cycling of GHG. Despite variations within and among different systems, low-latitude coastal upwelling systems typically act as a net carbon source to the atmosphere, while those at higher latitudes function as weak sinks or remain neutral regarding atmospheric CO2. These systems also significantly contribute to oceanic N2O and CH4 emissions, although the extent of their contribution to the latter remains poorly constrained. We also overview recent and future changes to upwelling systems in the context of a warmer climate and discuss uncertainties and implications for GHG production. Although rapid coastal warming is anticipated in all major coastal upwelling systems, the future changes in upwelling-favorable winds and their implications within the context of increased stratification are uncertain. Finally, we examine the major challenges that impede our ability to accurately predict how major coastal upwelling systems will respond to future climate change, and present recommendations for future research to better capture ongoing changes and disentangle natural and forced variability.

Published
2024

3. Boundaries of the Peruvian Oxygen Minimum Zone shaped by coherent mesoscale dynamics

Author

Bettencourt, João H., López, Cristóbal, García, Emilio Hernández, Montes, Ivonne, Sudre, Joël, Dewitte, Boris, Paulmier, Aurélien, and Garçon, Véronique

Subjects
Physics - Atmospheric and Oceanic Physics
Abstract

Dissolved oxygen in sea water is a major factor affecting marine habitats and biogeochemical cycles. Oceanic zones with oxygen deficits represent significant portions of the area and volume of the oceans and are thought to be expanding. The Peruvian oxygen minimum zone is one of the most pronounced and lies in a region of strong mesoscale activity in the form of vortices and frontal regions, whose effect in the dynamics of the oxygen minimum zone is largely unknown. Here, we study this issue from a modeling approach and a Lagrangian point of view, using a coupled physical-biogeochemical simulation of the Peruvian oxygen minimum zone and finite-size Lyapunov exponent fields to understand the link between mesoscale dynamics and oxygen variations. Our results show that, at depths between 380 and 600 meters, mesoscale structures have a relevant dual role. First, their mean positions and paths delimit and maintain the oxygen minimum zone boundaries. Second, their high frequency fluctuations entrain oxygen across these boundaries as eddy fluxes that point towards the interior of the oxygen minimum zone and are one order of magnitude larger than mean fluxes. We conclude that these eddy fluxes contribute to the ventilation of the oxygen minimum zone.

Published
2015
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4. The reduction of plankton biomass induced by mesoscale stirring: a modeling study in the Benguela upwelling

Author

Hernández-Carrasco, Ismael, Rossi, Vincent, Hernández-García, Emilio, Garçon, Veronique, and López, Cristóbal

Subjects
Nonlinear Sciences - Chaotic Dynamics, Physics - Atmospheric and Oceanic Physics
Abstract

Recent studies, both based on remote sensed data and coupled models, showed a reduction of biological productivity due to vigorous horizontal stirring in upwelling areas. In order to better understand this phenomenon, we consider a system of oceanic flow from the Benguela area coupled with a simple biogeochemical model of Nutrient-Phyto-Zooplankton (NPZ) type. For the flow three different surface velocity fields are considered: one derived from satellite altimetry data, and the other two from a regional numerical model at two different spatial resolutions. We compute horizontal particle dispersion in terms of Lyapunov Exponents, and analyzed their correlations with phytoplankton concentrations. Our modelling approach confirms that in the south Benguela there is a reduction of biological activity when stirring is increased. Two-dimensional offshore advection and latitudinal difference in Primary Production, also mediated by the flow, seem to be the dominant processes involved. We estimate that mesoscale processes are responsible for 30 to 50% of the offshore fluxes of biological tracers. In the northern area, other factors not taken into account in our simulation are influencing the ecosystem. We suggest explanations for these results in the context of studies performed in other eastern boundary upwelling areas.

Published
2011
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5. Declining oxygen in the global ocean and coastal waters

Author

Breitburg, Denise, Levin, Lisa A., Oschlies, Andreas, Grégoire, Marilaure, Chavez, Francisco P., Conley, Daniel J., Garçon, Véronique, Gilbert, Denis, Gutiérrez, Dimitri, Isensee, Kirsten, Jacinto, Gil S., Limburg, Karin E., Montes, Ivonne, Naqvi, S. W. A., Pitcher, Grant C., Rabalais, Nancy N., Roman, Michael R., Rose, Kenneth A., Seibel, Brad A., Telszewski, Maciej, Yasuhara, Moriaki, and Zhang, Jing

Published
2018

6. List of Contributors

Author

Achterberg, Eric P., primary, Allen, Simon, additional, Alves, José C., additional, Aragon, David, additional, Au, Douglas, additional, Barnes, Christopher R., additional, Barus, Carole, additional, Beaton, Alex, additional, Bell, Ryan J., additional, Blouch, Pierre, additional, Brault, Patrice, additional, Carvalho, Filipa, additional, Cervantes, Pablo, additional, Chen Legrand, D., additional, Colas, Florent, additional, Cowles, Timothy, additional, Cruz, Nuno A., additional, David, Arnaud, additional, Fernandez, Joaquin del Rio, additional, Delauney, Laurent, additional, Delory, Eric, additional, Dewitte, Boris, additional, Ferreira, Bruno M., additional, Fischer, Albert, additional, Garçon, Veronique, additional, Glenn, Scott, additional, Harcourt, Robert, additional, Heupel, Michelle R., additional, Jirka, Simon, additional, Jońca, Justyna, additional, Jones, Clayton, additional, Jugeau, Benoit, additional, Kibelka, Gottfried P.G., additional, Kim Juniper, S., additional, Kohut, Josh, additional, Laspidou, Chrysi, additional, Leadbetter, Adam, additional, Leblond, Emilie, additional, Lédée, E.J.I., additional, Mahfuz, Hassan, additional, Manes, Carmem-Lara, additional, Martinez, Enoc, additional, Martinez, Sergio, additional, Matos, Aníbal C., additional, McDonnell, Janice, additional, McLean, Scott, additional, Memè, Simone, additional, Toma, Daniel Mihai, additional, Miles, Travis, additional, Sabet, Seyed Morteza, additional, Mowlem, Matthew, additional, Muñoz Parra, P., additional, O’Reilly, Tom, additional, Ove Möller, Klas, additional, Pearlman, Jay, additional, Petersen, Wilhelm, additional, Pirenne, Benoît, additional, Poli, Paul, additional, Precheur, Hervé, additional, Quemener, Loïc, additional, Ralston, Emily, additional, Ramos, Marcel, additional, Reitz, Anja, additional, Rieke, Matthes, additional, Roarty, Hugh, additional, Romanytsia, Ivan, additional, Round, Adrian, additional, Ruiz, Pablo, additional, Saba, Grace, additional, Schaap, Allison, additional, Schofield, Oscar, additional, Seroka, Greg, additional, Stasch, Christoph, additional, Striebig, Nicolas, additional, Timothy Short, R., additional, Toler, Strawn K., additional, Udyawer, Vinay, additional, Valladares, Maria, additional, Visbeck, Martin, additional, Walsh, Ian, additional, Wild-Allen, Karen, additional, Woerther, Patrice, additional, Woillez, Mathieu, additional, Wollschläger, Jochen, additional, Yi, Xu, additional, and Hunsucker, Kelli Zargiel, additional

Published
2019
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8. Perspectives and Integration in SOLAS Science

Author

Garçon, Véronique C., Bell, Thomas G., Wallace, Douglas, Arnold, Steve R., Baker, Alex, Bakker, Dorothee C. E., Bange, Hermann W., Bates, Nicholas R., Bopp, Laurent, Boutin, Jacqueline, Boyd, Philip W., Bracher, Astrid, Burrows, John P., Carpenter, Lucy J., de Leeuw, Gerrit, Fennel, Katja, Font, Jordi, Friedrich, Tobias, Garbe, Christoph S., Gruber, Nicolas, Jaeglé, Lyatt, Lana, Arancha, Lee, James D., Liss, Peter S., Miller, Lisa A., Olgun, Nazli, Olsen, Are, Pfeil, Benjamin, Quack, Birgit, Read, Katie A., Reul, Nicolas, Rödenbeck, Christian, Rohekar, Shital S., Saiz-Lopez, Alfonso, Saltzman, Eric S., Schneising, Oliver, Schuster, Ute, Seferian, Roland, Steinhoff, Tobias, Traon, Pierre-Yves Le, Ziska, Franziska, Liss, Peter S., editor, and Johnson, Martin T., editor

Published
2014
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26. General methodology for the derivation of high resolution oceanic data through information fusion at different scales

Author

Yahia, Hussein, Sudre, Joel, Hernandez-Carrasco, Ismael, Singh, Dharmendra, Brodu, Nicolas, Garbe, Christoph, Garçon, Veronique, Geometry and Statistics in acquisition data (GeoStat), Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), 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), Indian Institute of Technology Roorkee (IIT Roorkee), Universität Heidelberg, Projet ESA Oceanflux, ESA, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, [NLIN.NLIN-CD]Nonlinear Sciences [physics]/Chaotic Dynamics [nlin.CD], Wavelets decompositions, Multiscale methods, Superresolution, Ocean/atmosphere interaction
Abstract

International audience; Derivation of high-resolution (HR) spatial distribution of data is a fundamental problem in Earth observation, either in the case of physical variables or when the data is obtained as the output of a classification process. We show that the problem can be resolved through information fusion at different scales. In the case of physical intensive variables of fully developed turbulence, as encountered in satellite Oceanography and Ocean/Climate interactions, we show that the derivation of HR data can be solved using a new method based on an approximation of the energy cascade, expressed in a microcanonical formulation, and associated to turbulent signal provided by HR satellite data. The generality of the approach offers the opportunity to infer different oceanic signals from Low Resolution (LR) to HR. The basic idea is to use optimal cascading to decrease the spatial resolution of the HR signal, then use the signal available at LR, transmit that information along the scales back to higher spatial resolution using the cascade to obtain a new HR signal. The process has been successfully used to obtain oceanic currents [1, 2], oceanic partial pressure of CO2 [3], and more recently sea surface salinity. [1] H. Yahia, J. Sudre, C. Pottier and V. Garçon, 2010, Motion analysis in oceanographic satellite images using multiscale methods and the energy cascade, Pattern Recognition, DOI: 10.1016/J.patcog.2010.04.011.[2] J. Sudre, H. Yahia, O. Pont, and V. Garçon, 2015, Ocean turbulent dynamics at superresolution from optimal multiresolution analysis and multiplicative cascade, IEEE TGRS, DOI: 10.1109/TGRS.2015.2436431[3] I. Hernández-Carrasco, J. Sudre, V. Garçon, H. Yahia, C. Garbe, A. Paulmier, B. Dewitte, S. Illig, I. Dadou, M. González-Dávila, and J. M. Santana-Casiano, 2015, Reconstruction of super-resolution ocean pCO2 and air-sea fluxes of CO2 from satellite imagery in the southeastern Atlantic, Biogeosciences, DOI: 10.5194/bg-12-5229-2015

Published
2016

28. Inference of super-resolution ocean pCO2 and air-sea CO2 fluxes from non-linear and multiscale processing methods

Author

Hernandez-Carrasco, Ismael, Sudre, J., Garçon, Veronique, Yahia, Hussein, Dewitte, Boris, Garbe, Christoph, Illig, Serena, Montes, Ivonne, Dadou, I., Paulmier, Aurélien, Butz, André, Laboratoire d'Etudes en Géophysique et Océanographie Spatiales (LEGOS NOUMEA), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR065-Centre National de la Recherche Scientifique (CNRS), 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), DYNBIO LEGOS, Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Geometry and Statistics in acquisition data (GeoStat), Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Echanges Côte-Large (ECOLA), Image Processing and Modeling, Interdisciplinary Center for Scientific Computing (IWR), Universität Heidelberg [Heidelberg]-Universität Heidelberg [Heidelberg], Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Karlsruhe Institute of Technology (KIT), European Geophysical Union, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Universität Heidelberg [Heidelberg] = Heidelberg University-Universität Heidelberg [Heidelberg] = Heidelberg University

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, [NLIN.NLIN-CD]Nonlinear Sciences [physics]/Chaotic Dynamics [nlin.CD], [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, Physics::Atmospheric and Oceanic Physics
Abstract

International audience; In recent years the role of submesoscale activity is emerging as being more and more important to understand global ocean properties, for instance, for accurately estimating the sources and sinks of Greenhouse Gases (GHGs) at the air-sea interface. The scarcity of oceanographic cruises and the lack of available satellite products for GHG concentrations at high resolution prevent from obtaining a global assessment of their spatial variability at small scales. In this work we develop a novel method to reconstruct maps of CO2 fluxes at super resolution (4km) using SST and ocean colour data at this resolution, and CarbonTracker CO2 fluxes data at low resolution (110 km). The responsible process for propagating the information between scales is related to cascading properties and multiscale organization, typical of fully developed turbulence. The methodology, based on the Microcanonical Multifractal Formalism, makes use, from the knowledge of singularity exponents, of the optimal wavelet for the determination of the energy injection mechanism between scales. We perform a validation analysis of the results of our algorithm using pCO2 ocean data from in-situ measurements in the upwelling region of Namibia.

Published
2014

30. On the global estimates of geostrophic and Ekman surface currents

Author

Sudre, Joel, Maes, Christophe, Garçon, Veronique, DYNBIO LEGOS, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Océan du Large et Variabilité Climatique (OLVAC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), 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
VARIATION INTERANNUELLE, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, CIRCULATION OCEANIQUE, COURANT GEOSTROPHIQUE, VENT, COURANT SUPERFICIEL, COURANT EKMAN, MODELISATION, Physics::Atmospheric and Oceanic Physics, ANALYSE STATISTIQUE, Physics::Geophysics
Abstract

International audience; Surface currents in oceanic environments are of crucial importance because they transport momentum, heat, salt, and tracers over large distances that regulate both the local and large-scale climate conditions, and because they contribute to the Lagrangian displacement of floating material, ranging from living resources to marine pollution. In recent decades, the understanding of surface currents has benefited from the opportunity of observing sea level and wind stress via satellite-derived measurements. Combining these parameters into geostrophic and wind-driven components provides an estimate of surface currents with a quarter-degree horizontal resolution at a global scale and at a daily time scale. In the present study, improvements are made on the consideration of the time dependence of the main parameters implied in the determination of the Ekman wind-driven component, and on the treatment of the equatorial singularity. The resulting Geostrophic and Ekman Current Observatory (GEKCO) estimates were validated with independent observations from both Lagrangian and Eulerian perspectives. The statistics of comparison were significant over the globe for the 2000-2008 period. The only exception was the estimation of meridional current along the equator, which requires further developments of the dynamic model and, probably, more accurate measurements. Applications using our GEKCO surface current estimates in cross-disciplinary approaches from physical oceanography to marine ecology are presented and discussed.

Published
2013

31. Evaluation de la dynamique océanique à haute résolution satellitaire SST par fusion de données à différentes échelles spatiales

Author

Sudre, J., Yahia, Hussein, Garçon, Veronique, Pottier, Claire, 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), DYNBIO LEGOS, Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Geometry and Statistics in acquisition data (GeoStat), Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), DCT/PS/TVI, Centre National d'Études Spatiales [Toulouse] (CNES), Météofrance, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3)

Subjects
ACM: I.: Computing Methodologies/I.5: PATTERN RECOGNITION, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, ACM: I.: Computing Methodologies/I.4: IMAGE PROCESSING AND COMPUTER VISION, [NLIN.NLIN-CD]Nonlinear Sciences [physics]/Chaotic Dynamics [nlin.CD], [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract

National audience; La détermination du champ de vitesses à partir d'acquisitions synoptiques des océans par imagerie satellitaire à haute résolution spatiale (par exemple la température de surface SST correspondant à des données pour lesquelles le pixel représente une surface de 4km2 ou moins) consiste habituellement à considérer plusieurs occurrences temporelles et à estimer un champ de vitesse en utilisant des méthodes statistiques ou des caractéristiques image (flot optique). La signification physique des champs de vitesses ainsi obtenus est loin d'être établie, compte tenu du caractère turbulent et intermittent de la dynamique océanique. Dans cette étude, nous exposons une approche nouvelle et radicalement différente, fondée sur la fusion de données acquises à des échelles spatiales différentes mais correspondant à une même acquisition temporelle, et consistant à propager à travers les échelles spatiales la dynamique obtenue à basse résolution par des données altimétriques (géostrophiques ou agéostrophiques) vers la haute résolution des données SST. On obtient de cette manière une évaluation de la dynamique océanique à la résolution SST validée par des données de simulation issues d'un modèle (ROMS -Regional Ocean Modelling System). Cette approche à base de fusion de données suppose la connaissance des phénomènes de transferts d'énergie entre les échelles spatiales d'un signal turbulent. Nous détaillons une approche microcanonique (le formalisme multiéchelles microcanonique) qui permet cette détermination, et qui est issue de développement récents et généraux en analyse non-linéaire des signaux complexes, ce qui permet d'envisager sa généralisation pour la fusion de données complexes et turbulentes en météorologie.

Published
2011

32. Biomass changes and trophic amplification of plankton in a warmer ocean

Author

Chust, Guillem, Icarus Allen, J., Bopp, Laurent, Schrum, Corinna, Holt, Jason, Tsiaras, Kostas, Zavatarelli, Marco, Chifflet, Marina, Cannaby, Heather, Dadou, Isabelle, Daewel, Ute, Wakelin, Sarah L., Machu, Eric, Pushpadas, Dhanya, Butenschon, Momme, Artioli, Yuri, Petihakis, George, Smith, Chris, Garçon, Veronique, Goubanova, Katerina, Le Vu, Briac, Fach, Bettina A., Salihoglu, Baris, Clementi, Emanuela, Irigoien, Xabier, Chust, Guillem, Icarus Allen, J., Bopp, Laurent, Schrum, Corinna, Holt, Jason, Tsiaras, Kostas, Zavatarelli, Marco, Chifflet, Marina, Cannaby, Heather, Dadou, Isabelle, Daewel, Ute, Wakelin, Sarah L., Machu, Eric, Pushpadas, Dhanya, Butenschon, Momme, Artioli, Yuri, Petihakis, George, Smith, Chris, Garçon, Veronique, Goubanova, Katerina, Le Vu, Briac, Fach, Bettina A., Salihoglu, Baris, Clementi, Emanuela, and Irigoien, Xabier

Abstract

Ocean warming can modify the ecophysiology and distribution of marine organisms, and relationships between species, with nonlinear interactions between ecosystem components potentially resulting in trophic amplification. Trophic amplification (or attenuation) describe the propagation of a hydroclimatic signal up the food web, causing magnification (or depression) of biomass values along one or more trophic pathways. We have employed 3-D coupled physical-biogeochemical models to explore ecosystem responses to climate change with a focus on trophic amplification. The response of phytoplankton and zooplankton to global climate-change projections, carried out with the IPSL Earth System Model by the end of the century, is analysed at global and regional basis, including European seas (NE Atlantic, Barents Sea, Baltic Sea, Black Sea, Bay of Biscay, Adriatic Sea, Aegean Sea) and the Eastern Boundary Upwelling System (Benguela). Results indicate that globally and in Atlantic Margin and North Sea, increased ocean stratification causes primary production and zooplankton biomass to decrease in response to a warming climate, whilst in the Barents, Baltic and Black Seas, primary production and zooplankton biomass increase. Projected warming characterised by an increase in sea surface temperature of 2.29 ± 0.05 ºC leads to a reduction in zooplankton and phytoplankton biomasses of 11% and 6%, respectively. This suggests negative amplification of climate driven modifications of trophic level biomass through bottom-up control, leading to a reduced capacity of oceans to regulate climate through the biological carbon pump. Simulations suggest negative amplification is the dominant response across 47% of the ocean surface and prevails in the tropical oceans; whilst positive trophic amplification prevails in the Arctic and Antarctic oceans. Trophic attenuation is projected in temperate seas. Uncertainties in ocean plankton projections, associated to the use of single global and regional

Published
2014

34. Biomass changes and trophic amplification of plankton in a warmer ocean

Author

Chust, Guillem, primary, Allen, J. Icarus, additional, Bopp, Laurent, additional, Schrum, Corinna, additional, Holt, Jason, additional, Tsiaras, Kostas, additional, Zavatarelli, Marco, additional, Chifflet, Marina, additional, Cannaby, Heather, additional, Dadou, Isabelle, additional, Daewel, Ute, additional, Wakelin, Sarah L., additional, Machu, Eric, additional, Pushpadas, Dhanya, additional, Butenschon, Momme, additional, Artioli, Yuri, additional, Petihakis, George, additional, Smith, Chris, additional, Garçon, Veronique, additional, Goubanova, Katerina, additional, Le Vu, Briac, additional, Fach, Bettina A., additional, Salihoglu, Baris, additional, Clementi, Emanuela, additional, and Irigoien, Xabier, additional

Published
2014
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