FY 2022

Skin temperature correction for calculations of air-sea oxygen flux and annual net community production

Yang, B., S.R. Emerson, and M.F. Cronin

Geophys. Res. Lett., 49(3), e2021GL096103, doi: 10.1029/2021GL096103, View online (2022)

We evaluated the influence of skin temperature correction on the calculations of air-sea O₂ flux and annual net community production (ANCP). The skin temperature correction term (ΔT) was derived from the fifth generation European Center for Medium-Range Weather Forecasts Reanalysis, which has large spatial and temporal variations that are consistent with independent measurements on three ocean moorings from areas with very different air-sea heat flux and ΔT. The result revealed that ΔT is dominated by the cool skin effect (which leads to the increase in air-to-sea O₂ flux and decrease in ANCP), except for the equatorial region or summertime when the warm layer effect is significant. Using data from three Argo profiling floats in the subarctic, subtropical, and tropical Pacific as examples, the calculations indicated that the correction could lead to −1%–+36% difference in annual air-to-sea O₂ flux and −33%–+5% difference in ANCP.

Plain Language Summary. The skin of the ocean can be slightly cooler than the surface mixed layer due to net surface heat loss (cool skin effect), or slightly warmer due to extreme solar radiation (warm layer effect). We used the fifth generation European Center for Medium-Range Weather Forecasts Reanalysis (ERA5) to derive the skin temperature correction term (ΔT) for calculating the air-sea O₂ flux and the annual net carbon export (annual net community production, ANCP). ΔT derived from ERA5 has large spatial and temporal variations, and is consistent with independent measurements on three ocean moorings from areas with very different air-sea heat flux and ΔT. The result showed that ΔT is mostly dominated by the cool skin effect (which leads to the increase in air-to-sea O₂ flux and decrease in ANCP), except for the equatorial region or summertime when the warm layer effect is significant. Calculations using data from three profiling floats in the subarctic, subtropical, and tropical Pacific indicated that the correction could lead to −1%–+36% difference in annual air-to-sea O₂ flux and −33%–+5% difference in ANCP.