Interannual variability of the air-sea flux of oxygen in the North Atlantic

In studies using timeseries observations of atmospheric O-2/N-2 to infer th e fate of fossil fuel CO2, it has been assumed that multi-year trends in ob served O-2/N-2 are insensitive to interannual variability in air-sea fluxes of oxygen. We begin to address the validity of this assumption by investig ating the magnitude and mechanisms of interannual variability in the flux o f oxygen across the sea surface using a North Atlantic biogeochemical model . The model, based on the MIT ocean general circulation model, captures the gross patterns and seasonal cycle of nutrients and oxygen within the basin . The air-sea oxygen flux exhibits significant interannual variability in t he North Atlantic, with a standard deviation (0.36 mol m(-2) y(-1)) that is a large fraction of the mean (0.85 mol m(-2) y(-1)). This is primarily a c onsequence of variability in winter convection in the subpolar gyre.