Boutin¹, J., Y. Rangama¹, J. Etcheto¹, L. Merlivat¹, T. Takahashi², M. Frankignoulle³ and B. Delille³

¹Laboratoire d’Océanographie Dynamique et de Climatologie, Paris, France, Tel: 33 1 44 27 47 65, Fax: 33 1 44 27 38 05, E-mail: jacqueline.boutin@lodyc.jussieu.fr, ²Lamont Doherty Earth Observatory of Columbia University, Palisades, USA, and ³Université de Liège, Liège, Belgium

Air-sea CO₂ fluxes in the Southern Ocean inferred from satellite data 

Air-sea CO₂ fluxes in the Southern Ocean and their variability are studied using satellite data (wind speed (U), sea surface temperature (SST) and Chlorophyll a (Chl)). AVHRR SST and Seawifs Chl are used to 1) interpret observed pCO₂ and 2) extrapolate pCO₂ using regional and seasonal pCO₂-SST and pCO₂-Chl fits. In-situ pCO₂ are from CARIOCA drifters and ship measurements. Yearly fluxes are derived from CO₂ exchange coefficients computed with scatterometer U. In the Subantarctic Zone (SAZ) and in the Polar Zone south of Australia and New Zealand, pCO₂ and SST are anticorrelated except in areas with high Chl where Chl appears to control most of pCO₂ variability. Applying our extrapolation scheme, the yearly flux is -0.08GtC/yr over the region (60S-45S-125E-155W). This is 60% lower than estimates made with Takahashi (2002) Dp. This discrepancy is mainly due to differences in Dp from June to November. On another hand, from January to June, the absorbing flux inferred from our pCO₂ extrapolations (3.3mmol m-2 day-1) is only 20% smaller than the one deduced from Takahashi (2002) Dp. These fluxes are on the same order as the flux deduced from CARIOCA buoys in the SAZ (-3.8mmol m-2 day-1) that were west of this zone.