Increased CO 2 outgassing in February-May 2010 in the tropical Atlantic following the 2009 Pacific El Niño

International audience The fugacity of CO 2 ( f CO 2 ) has been measured underway during the voyages of a merchant ship sailing from France to Brazil since 2008. High f CO 2 values are observed in 2010, between approximately 8°S and 8°N, and are particularly pronounced in boreal spring. These high v...

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Published in:Journal of Geophysical Research: Oceans
Main Authors: Lefèvre, Nathalie, Caniaux, Guy, Janicot, Serge, Gueye, Abdou Karim
Other Authors: Échanges dans la couche de surface : des pôles aux tropiques (SURF), 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)-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)), 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), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS), Variabilité climatique tropicale et globale (VARCLIM)
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2013
Subjects:
Online Access:https://hal.science/hal-00873395
https://hal.science/hal-00873395/document
https://hal.science/hal-00873395/file/JGR%20Oceans%20-%202013%20-%20Lef%20vre%20-%20Increased%20CO2%20outgassing%20in%20February%25u2010May%202010%20in%20the%20tropical%20Atlantic%20following%20the%202009.pdf
https://doi.org/10.1002/JGRC.20107
Description
Summary:International audience The fugacity of CO 2 ( f CO 2 ) has been measured underway during the voyages of a merchant ship sailing from France to Brazil since 2008. High f CO 2 values are observed in 2010, between approximately 8°S and 8°N, and are particularly pronounced in boreal spring. These high values are explained by the anomalous situation occurring in the tropical Atlantic in 2010 after the 2009 El Niño in the Pacific. The weakening of the trade winds during the El Niño event contributes to an increase of sea surface temperatures in the tropical Atlantic and a northward shift of the intertropical convergence zone. The anomalous position of the intertropical convergence zone is accompanied by reduced precipitation in boreal spring and hence a higher than usual sea surface salinity. The year 2010 is also characterized by a strong positive Atlantic multidecadal oscillation index and a negative North Atlantic oscillation index that contribute to the tropical Atlantic warming. Positive anomalies of both surface temperature and salinity cause an increase of surface CO 2 , leading to a stronger outgassing of CO 2 in 2010 compared with 2009 and 2011. The main factor responsible for the CO 2 anomalies is the Pacific El Niño teleconnection. The Atlantic multidecadal oscillation index also contributes in the northern hemisphere, and the role of the North Atlantic oscillation is negligible.