Satellite-derived CO 2 flux in the surface seawater of the austral ocean south of Australia. International Journal of Remote Sensing

• Published in: International Journal of Remote Sensing
• Main Authors: Benallal, Mohamed, Moussa, Hadger, Lencina-Avila, J.M., Touratier, Franck, Goyet, Catherine, El Jai, M. C., Poisson, Alain, Poisson, N.
• Other Authors: Institut de Modélisation et d'Analyses en géo-environnement et santé - Espace Développement (IMAGES-Espace DEV), UMR 228 Espace-Dev, Espace pour le développement, Institut de Recherche pour le Développement (IRD)-Université de Perpignan Via Domitia (UPVD)-Avignon Université (AU)-Université de La Réunion (UR)-Université de Montpellier (UM)-Université de Guyane (UG)-Université des Antilles (UA)-Institut de Recherche pour le Développement (IRD)-Université de Perpignan Via Domitia (UPVD)-Avignon Université (AU)-Université de La Réunion (UR)-Université de Montpellier (UM)-Université de Guyane (UG)-Université des Antilles (UA), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: air–sea CO 2 flux; austral ocean south of Australia; [SDU]Sciences of the Universe [physics]; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; Antarc*; Antarctica; Austral Ocean; Southern Ocean
• Online Access: https://univ-perp.hal.science/hal-01484490; https://doi.org/10.1080/01431161.2017.1286054

International audience A step by step algorithm for air–sea CO 2 flux (F(CO 2 )) calculation from satellite parameters is presented in this study. Parameters used for F(CO 2 ) calculation are: (1) sea surface temperature (SST) and chlorophyll-a (chl-a) from Moderate Resolution Imaging Spectroradiometer Aqua (MODIS Aqua), (2) sea surface salinity (SSS) estimated from MODIS Aqua SST using multiple linear regression, (3) seawater CO 2 fugacity (f(CO 2 sw )) estimated by MODIS Aqua SST and chl-a using feedforward neural networks, (4) atmospheric CO 2 fugacity (f(CO 2 atm )) from the Cape Grim station, and (5) wind speed from the Quick and Advanced Scatterometer (QSCAT and ASCAT). In situ data provided by (1) the Surveillance de l’Océan Austral – Monitoring the Southern Ocean (SURVOSTRAL) project, (2) the Integrated Marine Observed System (IMOS) project, and (3) Mesures à l’INterface Eau-aiR de la Variabilité des échanges de CO 2 (MINERVE) project collected on the research vessel L’Astrolabe, are used to establish and validate the models. These models are then tested using remote sensing data. This work focus on the southern ocean from the south of Australia to the Antarctica coasts (between 43.5° S and 67° S), on the period of spring and Austral summer (from October to March, between 2002/2003 and 2014/2015). In each step, the result’s precision of experiments was determined by the root mean square error (RMSE). Results show (1) an improvement of satellite SSS estimation with a precision of ±0.16 using SST and latitude, (2) an estimation of f(CO 2 ) by satellite data with a good accuracy of ±9.45 µatm (0.96 Pa), and (3) a calculation of F(CO 2 ) using satellite data with a global RMSE of about ±3 mmol CO 2 m –2 day –1 . The interpolated F(CO 2 ) shows that, in the period of austral spring and summer, this region absorbs the atmospheric CO 2 , and becomes a stronger sink of CO 2 throughout the years (from an overall average absorption of about 2 mmol CO 2 m –2 day –1 in 2002/2003 to about 7 mmol CO 2 m –2 day –1 in ...