Global surface-ocean ip/isupCOsub2/sub/sup and sea–air COsub2/sub flux variability from an observation-driven ocean mixed-layer scheme

摘要

A temporally and spatially resolved estimate of the globalsurface-ocean CO₂ partial pressure field and the sea–air CO₂ fluxis presented,obtained by fitting a simple data-driven diagnostic model of ocean mixed-layer biogeochemistryto surface-ocean CO₂ partial pressure data from the SOCAT v1.5 database.Results include seasonal, interannual, and short-term (daily) variations.In most regions,estimated seasonality is well constrained from the data,and compares well to the widely used monthly climatology by Takahashi et al. (2009).Comparison to independent data tentatively supports the slightly higher seasonal variationsin our estimates in some areas.We also fitted the diagnostic model to atmospheric CO₂ data.The results of this are less robust,but in those areas where atmospheric signals are not strongly influenced by land flux variability,their seasonality is nevertheless consistent with the results based on surface-ocean data.From a comparison with an independent seasonal climatology of surface-ocean nutrient concentration,the diagnostic model is shown to capture relevant surface-ocean biogeochemical processes reasonably well.Estimated interannual variations will be presented and discussed in a companion paper.