Reconciling Observation and Model Trends in North Atlantic Surface CO2
|Author(s)||Lebehot Alice D.1, 2, 3, Halloran Paul Richard1, Watson Andrew J.1, McNeall Doug4, Ford David A.4, Landschuetzer Peter5, Lauvset Siv K.6, 7, Schuster Ute1|
|Affiliation(s)||1 : Univ Exeter, Coll Life & Environm Studies, Geog, Laver Bldg, Exeter, Devon, England.
2 : Univ Cape Town, Marine Res Inst, Dept Oceanog, Cape Town, South Africa.
3 : CSIR, SOCCO, Cape Town, South Africa.
4 : Met Off, Exeter, Devon, England.
5 : Max Planck Inst Meteorol, Hamburg, Germany.
6 : Bjerknes Ctr Climate Res, NORCE Norwegian Res Ctr, Bergen, Norway.
7 : Univ Bergen, Bjerknes Ctr Climate Res, Geophys Inst, Bergen, Norway.
|Source||Global Biogeochemical Cycles (0886-6236) (Amer Geophysical Union), 2019-10 , Vol. 33 , N. 10 , P. 1204-1222|
|WOS© Times Cited||6|
The North Atlantic Ocean is a region of intense uptake of atmospheric CO2. To assess how this CO2 sink has evolved over recent decades, various approaches have been used to estimate basin-wide uptake from the irregularly sampled in situ CO2 observations. Until now, the lack of robust uncertainties associated with observation-based gap-filling methods required to produce these estimates has limited the capacity to validate climate model simulated surface ocean CO2 concentrations. After robustly quantifying basin-wide and annually varying interpolation uncertainties using both observational and model data, we show that the North Atlantic surface ocean fugacity of CO2 (fCO(2-ocean)) increased at a significantly slower rate than that simulated by the latest generation of Earth System Models during the period 1992-2014. We further show, with initialized model simulations, that the inability of these models to capture the observed trend in surface fCO(2-ocean) is primarily due to biases in the models' ocean biogeochemistry. Our results imply that current projections may underestimate the contribution of the North Atlantic to mitigating increasing future atmospheric CO2 concentrations.