Inshore Altimetry:Validation of Coastalt Products in the Strait of Gibraltar
Gomez-Enri, Jesus1; Torres, José Ramón2; Tejedor, Begoña3; Cipollini, Paolo4; Scozzari, Andrea5; Vignudelli, Stefano6; Roque, David7
1University of Cadiz, SPAIN; 2Instituto Hidrográfico de la Marina, SPAIN; 3Applied Physics Department (University of Cadiz), SPAIN; 4National Oceanography Centre, UNITED KINGDOM; 5ConsiglioNazionale delle Ricerche (CNR-ISTI), ITALY; 6Consiglio Nazionale delle Ricerche (CNR-IBF), ITALY; 7Instituto de Ciencias Marinas de Andalucía (CSIC), SPAIN
High spatial resolution altimetry data (18 Hz) from RA-2 Envisat have been validated, using two tide gauges located in Tarifa and Ceuta, which are in the area surrounding the Strait of Gibraltar.The altimeter data used for this study are the outputs of the processor originally developed under the framework of the COASTALT project and now being upgraded within the ESA DUE eSurge Project. The processor retracks waveforms at 18 Hz rate (i.e., with an approximate spacing of 350 m along-track), with some dedicated retrackers for coastal areas including a Brown waveform model with the addition of a Gaussian peak (BGP) as described by Halimi et al., 2012. High resolution altimeter-derived sea level data from May 2003 to May 2010 have been analyzed along the descending pass#180, which crosses the study area with a land-to-ocean and an ocean-to-land transition that covers a track-segment of about 30 km. Preliminary comparisons against in-situ data show correlation coefficients of 0.9 in the Algeciras Bay, even with only 29% of valid altimeter data. In the Strait of Gibraltar, higher correlation coefficients were found with about 86% of valid data.