Sea level variations and topography of the Arcachon Bay using satellite altimetry

Frédéric Frappart (Observatoire Midi-Pyrénées, France)


Alexandra Spodar (EPOC, France); Vincent Marieu (EPOC, France); Jean-Paul Parisot (EPOC, France); Hervé Deriennic (EPOC, France)

Event: 2014 Ocean Surface Topography Science Team Meeting

Session: Regional and Global CAL/VAL for Assembling a Climate Data Record

Presentation type: Type Poster

Satellite radar altimetry was developed to accurately measure ocean surface topography. Important effort in the development of new applications of altimetry is oriented towards extending the capabilities of current and future altimeters as close as possible to the coast.
The Arcachon Bay, on the southwest coast of France, was flown over by the RA-2 radar altimetry mission onboard ENVISAT over 2003-2012, and has been under the AltiKa radar altimetry mission onboard Saral track since February 2013. First comparisons between Saral altimetry measurements with Arcachon-Eyrac tide gauge records, located at a few hundred meters from the altimeter track, show that radar altimetry is able to retrieve the sea surface height within a few centimeters. These comparisons will be extended to the whole Envisat RA-2 period. They will permit to assess the accuracy and the biases of the two altimetry missions in coastal zone.
Besides, along-track profiles present variations consistent with the bathymetry of the Bay at low tide. Comparisons with Lidar topography from 2005 and sparse Lidar altimetry measurements from the ICESat mission from 2003 to 2009 will be presented to estimate the accuracy of radar altimetry at both Ku (frequency of 13.5 GHz for ENVISAT RA-2) and Ka (frequency of 35.5 GHz for Saral AltiKa) for along-track topography of the intertidal zone.
Frédéric Frappart
Observatoire Midi-Pyrénées