CoAuthors

Anny Cazenave (CNES-LEGOS, France); Benoit Meyssignac (CNES-LEGOS, France); Robin Chevrier (CNES-LEGOS, France); Thierry Delcroix (IRD-LEGOS, France)

By making use of 20th century coupled climate models with and without external forcing, and 2-D past sea level reconstruction, studies of Meyssignac et al., 2012 have shown that in the tropical Pacific, the regional sea level variability is mainly dominated by the internal variability of the ocean-atmosphere system. However, few recent studies (e.g. Han et al., 2013) have indicated the possible influence of anthropogenic forcing on tropical Pacific regional sea level variability at present and in future. In our study, by making use of different sets of CMIP5 runs (climate model used by IPCC), we focus on separating the contribution of anthropogenic forcing (signal) and internal climate variability (noise) to the Pacific Ocean regional sea level variability during the 20th and 21st century and we analyze the temporal evolution of this signal/noise ratio. In general, in each of the CMIP5 runs, the internal climate variability is taken into account at different time phases. Performing an ensemble mean of several such runs will therefore compensate this internal variability thereby giving an estimate of regional sea level variability driven by the anthropogenic forcing. By removing the anthropogenic driven sea level variability from each of CMIP5 runs, the evolution of the internal climate variability is studied.