Transports and budgets of anthropogenic CO 2 in the tropical North Atlantic in 1992–1993 and 2010–2011

The meridional transport of anthropogenic CO 2 (C ant ) in the tropical North Atlantic (TNA) is investigated using data from transoceanic sections along 7.5°N and 24.5°N, carried out in the early 1990s and 2010s. The net C ant transport across both sections is northward. At 7.5°N, this transport increased from 315 ± 47 kmol s −1 in 1993 to 493 ± 51 kmol s −1 in 2010; similarly, across 24.5°N it grew from 530 ± 46 kmol s −1 in 1992 to 662 ± 49 kmol s −1 in 2011. These changes result from modifications in the intermediate and deep circulation patterns, as well as from C ant increase within the thermocline waters. In deep waters, lateral advection causes a net C ant input of 112 ± 60 kmol s −1 (234 ± 65 kmol s −1 ) in 1992–1993 (2010–2011); within these deep waters, the storage rate of C ant is not statistically different from the net C ant input, 139 ± 21 kmol s −1 (188 ± 21 kmol s −1 ) in 1992–1993 (2010–2011). The C ant increase in deep waters is due to the large injection of C ant across the 24.5°N by the Deep Western Boundary Current and the northward recirculation of North Atlantic Deep Water along 7.5°N. In contrast, a large net C ant output in the upper layer is caused by the Florida Current. Despite this net C ant output, the C ant accumulates at a rate of 215 ± 24 kmol s −1 (291 ± 24 kmol s −1 ) referenced to year 1993 (2010). From the two C ant budgets, we infer a C ant air‐sea flux of 0.23 ± 0.02 Pg yr −1 in the TNA, much larger than previous estimates.