Abstract
Estimates of the anthropogenic global-integrated sea-air carbon dioxide (CO2) fluxfrom 1990 to 2009, based on different models and measurements, range from−1.4to−2.6 PgC yr−1. The median values of anthropogenic CO2for each method showbetter agreement and are:−1.9 for Pg C yr−1for numerical ocean general circulation hind cast models (OGCMs) with parameterized biogeochemistry;−2.1 PgC yr−1for at-mospheric inverse models;−1.9 PgC yr−1for global atmospheric constraints based onO2/ N2ratios for 1990–2000; and−2.4 PgC yr−1for oceanic inverse models. An up-dated estimate of this anthropogenic CO2flux based on a climatology of sea-air partialpressure of CO2differences (∆pCO2) (Takahashi et al., 2009) and a bulk formulation of gas transfer with wind speed for year 2000 is−2.0 PgC yr−1. Using this∆pCO2climatology and empirical relationships ofpCO2with sea-surface temperature (SST)anomalies (Park et al., 2010a), the interannual variability of the contemporary CO2flux is estimated to be 0.20Pg C yr−1(1σ) from 1990 through 2009. This is similar tothe variability estimated by the OGCMs of 0.16 Pg Cyr−1but smaller than the interannual variability from atmospheric inverse estimates of 0.40Pg C yr−1. The variability islargely driven by large-scale climate re-organizations. The decadal trends for differentmethods range from−0.13 (Pg Cyr−1) decade−1to−0.50 (Pg Cyr−1) decade−1. TheOGCMs and the data based sea-air CO2flux estimates show smaller uptakes and ap-preciably smaller decadal trends than estimates based on changes in carbon inventory suggesting that methods capable of resolving shorter timescales are showing a slow-ing of the rate of ocean CO2uptake. It is not clear if this large difference in trend is amethodological issue or a real natural feedback Show more
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https://doi.org/10.3929/ethz-b-000062884Publication status
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Biogeosciences DiscussionsVolume
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CopernicusOrganisational unit
03731 - Gruber, Nicolas / Gruber, Nicolas
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Is previous version of: https://doi.org/10.3929/ethz-b-000065788
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