Interannual variability of the oceanic sink of CO 2 from 1979 through 1997

• Published in: Global Biogeochemical Cycles
• Main Authors: Le Quéré, Corinne, Orr, James C., Monfray, Patrick, Aumont, Olivier, Madec, Gurvan
• Other Authors: University of East Anglia Norwich (UEA), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), National Institute for Earth Science and Astronomy (INSU-CNRS), Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'océanographie dynamique et de climatologie (LODYC), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2000
• Subjects: Oceanography: Biological and Chemical: Carbon cycling; Oceanography: Physical: El Nino; Oceanography: General: Climate and interannual variability; [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph]; [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; Antarctic; Pacific; Antarc*; North Atlantic; North Atlantic oscillation
• Online Access: https://hal.science/hal-00772170; https://hal.science/hal-00772170/document; https://hal.science/hal-00772170/file/1999GB900049.pdf; https://doi.org/10.1029/1999GB900049

International audience We have estimated the interannual variability in the oceanic sink of CO 2 with a three-dimensional global-scale model which includes ocean circulation and simple biogeochemistry. The model was forced from 1979 to 1997 by a combination of daily to weekly data from the European Center for Medium-Range Weather Forecast and the National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis as well as European Remote Sensing satellite observations. For this period, the ocean sink of CO 2 is estimated to vary between 1.4 and 2.2 Pg C yr -1 , as a result of annually averaged interannual variability of +/-0.4 Pg C yr -1 that fluctuates about a mean of 1.8 Pg C yr -1 . Our interannual variability roughly agrees in amplitude with previous ocean-based estimates but is 2 to 4 times less than estimates based on atmospheric observations. About 70% of the global variance in our modeled flux of CO 2 originated in the equatorial Pacific. In that region, our modeled variability in the flux of CO 2 generally agreed with that observed to +/-0.1 Pg C yr -1 . The predominance of the equatorial Pacific for interannual variability is caused by three factors: (1) interannual variability associated with El Niño events occurs in phase over the entire basin, whereas elsewhere positive and negative anomalies partly cancel each other out (e.g., for events such as Antarctic Circumpolar Wave and the North Atlantic Oscillation); (2) dynamic processes dominate in the equatorial Pacific, whereas dynamic, thermodynamic, and biological processes partly cancel one another at higher latitudes; and (3) our model underestimates the variability in ocean dynamics and biology at high latitudes.