FY 2003

A first estimate of present and preindustrial air-sea CO₂ flux patterns based on ocean interior carbon measurements and models

Gloor, M., N. Gruber, J.L. Sarmiento, C.L. Sabine, R.A. Feely, and C. Rödenbeck

Geophys. Res. Lett., 30(1), 1010, doi: 10.1029/2002GL015594 (2003)

The exchange of CO across the air-sea interface is a main determinant of the distribution of atmospheric CO from which major conclusions about the carbon cycle are drawn, yet our knowledge of atmosphere-ocean fluxes still has major gaps. A new analysis based on recent ocean dissolved inorganic carbon data and on models permits us to separately estimate the preindustrial and present air-sea CO flux distributions without requiring knowledge of the gas exchange coefficient. We find a smaller carbon sink at mid to high latitudes of the southern hemisphere than previous data based estimates and a shift of ocean uptake to lower latitude regions compared to estimates and simulations. The total uptake of anthropogenic CO for 1990 is 1.8 (±0.4) Pg C yr. Our ocean based results support the interpretation of the latitudinal distribution of atmospheric CO data as evidence for a large northern hemisphere land carbon sink.