Coastal altimetry and sea level change in selected test areas along the European coast
Luciana Fenoglio-Marc(1) , Matthias Becker(1) , Guy Woppelmann(2) , Mikhail Karpytchev(2) , and Marta Marcos(3)
Darmstadt University of Technology,
(2) University de la Rochelle, Avenue Michel Crepeau , F-17042 La Rochelle, France
(3) University de la Rochelle , Avenue Michel Crepeau , F-17042 La Rochelle, France , France
The accuracy of satellite altimeter measurements instantaneous sea surface heights is lower in coastal regions than in the open ocean, due to contamination of land in the radar altimeter and in the radiometer measurements, that causes the sea level height and wet-tropospheric correction from on-board radiometer to be less accurate.
The accuracy of the some of the standard corrections applied to the satellite altimeter measurements is lower in coastal areas. This is true for the ocean-tide correction and for the classical inverse barometer corrections, that is inaccurate in semi-closed seas.
The land contamination in the footprint is here investigated at selected locations along the European shelf.
Alternative environmental corrections for ocean-tide, wet-troposhere and inverse barometer corrections are investigated and a dedicated waveform processing is used to improve the quality of the altimeter measurements.
The resulting sea level height variability is checked using both in-situ data and local models. A high resolution coastal hydrodynamics model is used to account for the tidal amplification between the satellite trace and the tide gauge. Both variability and absolute height of sea level are investigated at tide gauge stations where GPS measurements are available.
Residual bias and drift between the multi-mission altimeter data are estimated from quasi-simultaneous measurements from altimeter and tide gauge stations.
Two regions are selected for their different and complementary characteristics: the western Mediterranean Sea near Toulon and the Gulf of Biscay near La Rochelle.