Update on the temperature corrections of global air-sea CO2 flux estimates
Dong, Y.; Bakker, D.C.E.; Bell, T.G.; Huang, B.; Landschützer, P.; Liss, P.S.; Yang, M. (2022). Update on the temperature corrections of global air-sea CO2 flux estimates. Global Biogeochem. Cycles 36(9): e2022GB007360. https://dx.doi.org/10.1029/2022gb007360 In: Global Biogeochemical Cycles. American Geophysical Union: Washington, DC. ISSN 0886-6236; e-ISSN 1944-9224, more |   |
| Authors | | Top | - Dong, Y.
- Bakker, D.C.E.
- Bell, T.G.
- Huang, B.
| - Landschützer, P., more
- Liss, P.S.
- Yang, M.
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| Abstract | The oceans are a major carbon sink. Sea surface temperature (SST) is a crucial variable in the calculation of the air-sea carbon dioxide (CO2) flux from surface observations. Any bias in the SST or any upper ocean vertical temperature gradient (e.g., the cool skin effect) potentially generates a bias in the CO2 flux estimates. A recent study suggested a substantial increase (∼50% or ∼0.9 Pg C yr−1) in the global ocean CO2 uptake due to this temperature effect. Here, we use a gold standard buoy SST data set as the reference to assess the accuracy of insitu SST used for flux calculation. A physical model is then used to estimate the cool skin effect, which varies with latitude. The bias-corrected SST (assessed by buoy SST) coupled with the physics-based cool skin correction increases the average ocean CO2 uptake by ∼35% (0.6 Pg C yr−1) from 1982 to 2020, which is substantially smaller than the previous correction. After these temperature considerations, we estimate an average net ocean CO2 uptake of 2.2 ± 0.4 Pg C yr−1 from 1994 to 2007 based on an ensemble of surface observation-based flux estimates, in line with the independent interior ocean carbon storage estimate corrected for the river induced natural outgassing flux (2.1 ± 0.4 Pg C yr−1). |
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