CoAuthors

Marcellin Nonti (LEGOS / Université de Cotonou, Benin); Baptiste Chide (LEGOS / Supaéro, France); Benoit Meyssignac (LEGOS / CNES, France); Florence Birol (LEGOS , France)

Since 1993, altimetry has provided an unprecedented opportunity to study sea level variability with a quasi-global coverage. Satellite altimetry indicates that sea level has been rising fast in response to global warming, but with large regional variations. However, standard altimetric data do not allow to study sea level variability and rise close to the coast, where the socio-economic impacts of sea level rise are the greatest. Recently, along-track altimetric data have been reprocessed at LEGOS/CTOH using algorithms adapted to coastal regions to recover information in coastal zones (this reprocessed coastal product is referred to as the XTRACK dataset here).
In this study, we first intercalibrate the along-track Topex-Poséidon, Jason-1 and Jason-2 XTRACK dataset to that distributed by AVISO to have consistent sea level data in the open ocean. Then, sea level trends are computed with the XTRACK dataset to analyse how sea level rise varies as a function of the distance to the coast. Spectral analyses are performed to assess the frequency bands for which
coastal sea level variability and open ocean variability differ.
Analyses are performed over two regions (West coast of Africa and southwest Pacific). They will be extended to the global ocean to provide a map of sea level trends over the 1993-2012 period for the coastal zones of the global ocean.