Role of wind stress and heat fluxes in interannual-to-decadal variability of air-sea CO2 and O2 fluxes in the North Atlantic

A coupled ecosystem- circulation model of the North Atlantic is used to examine the individual contributions by wind stress and surface heat fluxes to naturally driven interannual- to- decadal variability of air- sea fluxes of CO2 and O-2 during 1948 - 2002. The model results indicate that variations in O-2 fluxes are mainly driven by variations in surface heat fluxes in the extratropics ( 15 degrees N to 70 degrees N), and by wind stress in the tropics ( 10 degrees S to 15 degrees N). Conversely, variations in simulated CO2 fluxes are predominantly windstress driven over the entire model domain ( 18 degrees S to 70 degrees N); while variability in piston velocity and surface heat fluxes is less important. The simulated uptake of O-2 by the North Atlantic amounts to 70 +/- 11 Tmol yr(-1) to which the subpolar region ( 45 degrees N to 70 degrees N) contributes by 62 +/- 10 Tmol yr(-1). Whereas the subpolar North Atlantic takes up more than 2/ 3 of the total carbon absorbed by the North Atlantic in our model ( about 0.3 Pg C yr(-1)), interannual variability of air- sea CO2 fluxes reaches similar values ( about 0.01 Pg C yr(-1) each) in the subpolar ( 45 degrees N to 70 degrees N), the subtropical ( 15 degrees N to 45 degrees N) and the equatorial ( 10 degrees S to 15 degrees N) Atlantic.