Basin‐Scale Estimate of the Sea‐Air CO 2 Flux During the 2010 Warm Event in the Tropical North Atlantic

• Published in: Journal of Geophysical Research: Biogeosciences
• Main Authors: Lefèvre, Nathalie, Veleda, Dóris, Tyaquiçã, Pedro, Perruche, Coralie, Diverrès, Denis, Ibánhez, J. Severino P.
• Other Authors: Austral, Boréal et Carbone (ABC), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Universidade Federal de Pernambuco Recife (UFPE), Mercator Océan, Société Civile CNRS Ifremer IRD Météo-France SHOM, Instrumentation, Moyens analytiques, Observatoires en Géophysique et Océanographie (IMAGO), Trinity College Dublin, European Project: 264879,EC:FP7:ENV,FP7-ENV-2010,CARBOCHANGE(2011), European Project: 633211,H2020,H2020-BG-2014-2,AtlantOS(2015)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; North Atlantic
• Online Access: https://hal.sorbonne-universite.fr/hal-02171810; https://hal.sorbonne-universite.fr/hal-02171810/document; https://hal.sorbonne-universite.fr/hal-02171810/file/Lef-vre_et_al-2019-Journal_of_Geophysical_Research__Biogeosciences.pdf; https://doi.org/10.1029/2018JG004840

Following the anomalous warming event occurring in the tropical North Atlantic in 2010, higher than usual surface fugacity of CO 2 ( f CO 2 ) was observed. To evaluate the spatial extent of these anomalies and their drivers, and to quantify the sea-air CO 2 flux at basin scale, the Mercator-Ocean model is used from 2006 to 2014 within the region 0-30°N, 70-15°W. Model outputs are generally in accordance with underway sea surface temperature, sea surface salinity, and surface f CO 2 recorded by two merchant ships. The anomalous warming of 2010 is well reproduced by the model and is the main driver of f CO 2 anomalies. The first coupled Empirical Orthogonal Function mode, between sea surface temperature and f CO 2 , captures more than 70% of the total variance and is characterized by a basin-scale warming associated to positive f CO 2 anomalies. The corresponding principal components are correlated to the Tropical North Atlantic Index and identify 2010 as the year with the highest positive anomaly over 2006-2014. Exceptions to this general pattern are located near the African coast, where the weakening of the coastal upwelling causes negative inorganic carbon anomalies, and close to the Amazon River plume, where f CO 2 anomalies are primarily associated with sea surface salinity anomalies. Although the f CO 2 anomalies of 2010 appear mostly in spring, they affect the annual CO 2 budget and lead to an increased CO 2 outgassing twice as large (46.2 Tg C per year) as the mean annual flux over the 2006-2014 period (23.3 Tg C per year).