A global, open-ocean model of carbonyl sulfide and its air-sea flux

A global, open-ocean, climatological model of marine carbonyl sulfide (OCS) with diurnal, seasonal, vertical and latitudinal resolution is presented a nd analyzed. The model includes the processes of photchemical production, a ir-sea gas exchange, vertical turbulent mixing, and hydrolysis. In accordan ce with observations, the model predicts the highest surface OCS concentrat ions during the summer in high latitudes. The model with the best guess set of parameters predicts the open ocean to be a sink of OCS (2.3 Gmol yr(-1) ) but severely underpredicts surface OCS concentrations in most locations. When a simple temperature-dependent dark production parameterization is inc luded, the ocean becomes a source of OCS (2.1 Gmol yr(-1)). In addition to dark production, the model is most sensitive to the surface concentration o f colored dissolved organic matter (CDOM) and the spectral slope of CDOM ab sorption.