A global estimate of the full oceanic C-13 Suess effect since the preindustrial

摘要

We present the first estimate of the full global ocean C-13 Suess effect since preindustrial times, based on observations. This has been derived by first using the method of Olsen and Ninnemann (2010) to calculate C-13 Suess effect estimates on sections spanning the world ocean, which were next mapped on a global 1 degrees x 1 degrees grid. We find a strong C-13 Suess effect in the upper 1000mof all basins, with strongest decrease in the subtropical gyres of the Northern Hemisphere, where delta C-13 of dissolved inorganic carbon has decreased by more than 0.8 since the industrial revolution. At greater depths, a significant C-13 Suess effect can only be detected in the northern parts of the North Atlantic Ocean. The relationship between the C-13 Suess effect and the concentration of anthropogenic carbon varies strongly between water masses, reflecting the degree to which source waters are equilibrated with the atmospheric C-13 Suess effect before sinking. Finally, we estimate a global ocean inventory of anthropogenic CO2 of 92 +/- 46 Gt C. This provides an estimate that is almost independent of and consistent, within the uncertainties, with previous estimates.