Altimetry-based sea level trends along the coasts of Western Africa
25 years of progress in radar altimetry
Marti, F.
Cazenave, A.
Birol, F.
Passaro, M.
Leger, F.
/Nino, Fernando
/Almar, Rafaël
Benveniste, J.
Legeais, J. F.
Satellite altimetry
Sea level
Coastal zones
We present results of contemporary coastal sea level changes along the coasts of Western Africa, obtained from a dedicated reprocessing of satellite altimetry data done in the context of the ESA 'Climate Change Initiative' sea level project. High sampling rate (20 Hz) sea level data from the Jason-1 and Jason-2 missions over a 14-year-long time span (July 2002 to June 2016) are considered. The data were first retracked using the ALES adaptative leading edge subwaveform retracker. The X-TRACK processing system developed to optimize the completeness and accuracy of the corrected sea level time series in coastal ocean areas was then applied. From the 14-year long sea level time series finally obtained, we estimate sea level trends along the Jason-1 & 2 tracks covering the study region. We analyze regional variations in sea level trends, with a focus on the changes observed between the open ocean to the coastal zone. Compared to the conventional 1 Hz sea level products dedicated to open ocean applications, the retracked 20 Hz measurements used in this study allow us to retrieve valid sea level information much closer to the coast (less than 3-4 km to the coast, depending on the satellite track location). The main objective of this study is twofold: (1) provide sea level products in the coastal areas from reprocessed altimetry data and (2) check whether sea level changes at the coast differ from that reported in the open ocean with conventional altimetry products. In the selected region, results show that over the study period, sea level trends observed near the coast of Western Africa are significantly different than offshore trends. In order to assess the robustness of the results, detailed analyses are performed at several locations to discriminate between possible drifts in the geophysical corrections and physical processes potentially able to explain the sea level changes observed close to the coast.
Benveniste J. (ed.)
Bonnefond P. (ed.)
2021
text
https://www.documentation.ird.fr/hor/fdi:010082138
oai:ird.fr:fdi:010082138
Marti F., Cazenave A., Birol F., Passaro M., Leger F., Nino Fernando, Almar Rafaël, Benveniste J., Legeais J. F.. Altimetry-based sea level trends along the coasts of Western Africa. In : Benveniste J. (ed.), Bonnefond P. (ed.), . 25 years of progress in radar altimetry 2021, 68 (2 No Spécial), 504-522
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