| Summary: | This is the final version of the article. Available from AGU via the DOI in this record. The Southern Ocean (SO) carbon sink has strengthened substantially since the year 2000, following a decade of a weakening trend. However, the surface ocean pCO2 data underlying this trend reversal are sparse, requiring a substantial amount of extrapolation to map the data. Here, we use 9 different pCO2 mapping products to investigate the SO trends and their sensitivity to the mapping procedure. We find a robust temporal coherence for the entire SO, with 8 of the 9 products agreeing on the sign of the decadal trends, i.e., a weakening CO2 sink trend in the in the 1990s (on average 0.22±0.24 Pg C yr−1 decade−1), and a strengthening sink trend during the 2000s (-0.35±0.23 Pg C yr−1 decade−1). Spatially, the multi-product mean reveals rather uniform trends, but the confidence is limited, given the small number of statistically significant trends from the individual products, particularly during the data sparse 1990-1999 period. The main body of this work was supported by ETH.
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