SeaFlux: harmonization of air–sea CO 2 fluxes from surface p CO 2 data products using a standardized approach

[摘要] Air–sea flux of carbon dioxide (CO 2 ) is a critical componentof the global carbon cycle and the climate system with the ocean removingabout a quarter of the CO 2 emitted into the atmosphere by humanactivities over the last decade. A common approach to estimate this net fluxof CO 2 across the air–sea interface is the use of surface oceanCO 2 observations and the computation of the flux through a bulkparameterization approach. Yet, the details for how this is done in order toarrive at a global ocean CO 2 uptake estimate vary greatly, enhancingthe spread of estimates. Here we introduce the ensemble data product,SeaFlux (Gregor and Fay, 2021, https://doi.org/10.5281/zenodo.5482547 ​​​​​​​, https://github.com/luke-gregor/pySeaFlux , last access: 9 September 2021​​​​​​​); this resource enables users toharmonize an ensemble of products that interpolate surface ocean CO 2 observations to near-global coverage with a common methodology to fill inmissing areas in the products. Further, the dataset provides the inputs tocalculate fluxes in a consistent manner. Utilizing six globalobservation-based mapping products (CMEMS-FFNN, CSIR-ML6, JENA-MLS, JMA-MLR,MPI-SOMFFN, NIES-FNN), the SeaFlux ensemble approach adjusts formethodological inconsistencies in flux calculations. We address differencesin spatial coverage of the surface ocean CO 2 between the mappingproducts, which ultimately yields an increase in CO 2 uptake of up to17 % for some products. Fluxes are calculated using three wind products(CCMPv2, ERA5, and JRA55). Application of a scaled gas exchange coefficienthas a greater impact on the resulting flux than solely the choice of windproduct. With these adjustments, we present an ensemble of global surfaceocean p CO 2 and air–sea carbon flux estimates. This work aims to supportthe community effort to perform model–data intercomparisons which will helpto identify missing fluxes as we strive to close the global carbon budget.

[学科分类] 眼科学