Estimates of anthropogenic carbon uptake from four three-dimensional global ocean models

• Published in: Global Biogeochemical Cycles
• Main Authors: Orr, James C., Maier-Reimer, Ernst, Mikolajewicz, U., Monfray, Patrick, Sarmiento, Jorge L., Toggweiler, J. R., Taylor, N. K., Palmer, J., Gruber, Nicolas, Sabine, Christopher L., Le Quéré, Corinne, Key, Robert M., Boutin, Jacqueline
• Other Authors: 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)), 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)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Max-Planck-Institut für Meteorologie (MPI-M), Max-Planck-Gesellschaft, Atmospheric and Oceanic Sciences Program Princeton (AOS Program), NOAA Geophysical Fluid Dynamics Laboratory (GFDL), National Oceanic and Atmospheric Administration (NOAA)-National Oceanic and Atmospheric Administration (NOAA)-Princeton University, National Oceanic and Atmospheric Administration (NOAA), Met Office Hadley Centre (MOHC), United Kingdom Met Office Exeter, Universität Bern / University of Bern (UNIBE), Princeton University, 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 2001
• Subjects: [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]; [SDE.MCG]Environmental Sciences/Global Changes; Southern Ocean
• Online Access: https://hal.science/hal-00153888; https://hal.science/hal-00153888/document; https://hal.science/hal-00153888/file/2000GB001273.pdf; https://doi.org/10.1029/2000GB001273

We have compared simulations of anthropogenic CO$_2$ in the four threedimensional ocean models that participated in the first phase of the Ocean Carbon-Cycle Model Intercomparison Project (OCMIP), as a means to identify their major differences.Simulated global uptake agrees to within $\pm$19%, giving a range of 1.85$\pm$0.35 PgC yr$^{-1}$ for the 1980-1989 average. Regionally, the Southern Ocean dominates the present-day air-sea flux of anthropogenic CO$_2$ in all models, with one third to one half of the global uptake occurring south of 30°S. The highest simulated total uptake in the Southern Ocean was 70% larger than the lowest. Comparison with recent data-based estimates of anthropogenic CO$_2$ suggesthat most of the models substantially overestimate storage in the Southern Ocean; elsewhere they generally underestimate storage by less than 20%. Globally, the OCMIP models appear to bracket the real ocean's present uptake, based on comparison of regional data-basedstimates of anthropogenic CO$_2$ and bomb $^{14}$C. Column inventories of bomb $^{14}$C have become more similar to those for anthropogenic CO$_2$ with the time that has elapsed between the Geochemical Ocean Sections Study (1970s) and Word Ocean Circulation Experiment (1990s) global sampling campaigns. Our ability to evaluate simulated anthropogenic CO$_2$ would improve if systematic errors associated with the data-based estimates could be provided regionally.