An Assessment of CO2 Storage and Sea‐Air Fluxes for the Atlantic Ocean and Mediterranean Sea Between 1985 and 2018

• Main Authors: Pérez, Fiz F., Becker, Meike, Goris, Nadine, Gehlen, Marion, López-Mozos, Marta, Tjiputra, Jerry, Olsen, Are, Müller, Jens Daniel, Huertas, I. Emma, Chau, Thi-Tuyet-Trang, Caínzos, Verónica, Velo, A., Bernard, G., Hauck, Judith, Gruber, Nicolas, Wanninkhof, Rik
• Other Authors: Agencia Estatal de Investigación (España), European Commission, Research Council of Norway, Bjerknes Centre for Climate Research, Helmholtz Association, National Oceanic and Atmospheric Administration (US)
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2024
• Subjects: Southern Ocean
• Online Access: http://hdl.handle.net/10261/354481; https://doi.org/10.1029/2023GB007862

31 pages, 8 figures, 1 table.-- This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License As part of the second phase of the Regional Carbon Cycle Assessment and Processes project (RECCAP2), we present an assessment of the carbon cycle of the Atlantic Ocean, including the Mediterranean Sea, between 1985 and 2018 using global ocean biogeochemical models (GOBMs) and estimates based on surface ocean carbon dioxide (CO2) partial pressure (pCO2 products) and ocean interior dissolved inorganic carbon observations. Estimates of the basin-wide long-term mean net annual CO2 uptake based on GOBMs and pCO2 products are in reasonable agreement (−0.47 ± 0.15 PgC yr−1 and −0.36 ± 0.06 PgC yr−1, respectively), with the higher uptake in the GOBM-based estimates likely being a consequence of a deficit in the representation of natural outgassing of land derived carbon. In the GOBMs, the CO2 uptake increases with time at rates close to what one would expect from the atmospheric CO2 increase, but pCO2 products estimate a rate twice as fast. The largest disagreement in the CO2 flux between GOBMs and pCO2 products is found north of 50°N, coinciding with the largest disagreement in the seasonal cycle and interannual variability. The mean accumulation rate of anthropogenic CO2 (Cant) over 1994–2007 in the Atlantic Ocean is 0.52 ± 0.11 PgC yr−1 according to the GOBMs, 28% ± 20% lower than that derived from observations. Around 70% of this Cant is taken up from the atmosphere, while the remainder is imported from the Southern Ocean through lateral transport F. F. Pérez and A. Velo were supported by the BOCATS2 (PID2019-104279GB-C21) project funded by MCIN/AEI/10.13039/501100011033 and by European Union under grant agreement no. 101094690 (EuroGO-SHIP), and with E. Huertas contributed to WATER:iOS CSIC PTI. M. Becker acknowledges funding from the Research Council of Norway through N-ICOS-2 (Grant 296012), and Nansen Legacy, Grant 276730. N. Goris was supported by the strategic project ...