Research

High resolution Gravity Field Modelling Using SAR Altimetry in the Northeast Atlantic Ocean

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Abstract

Over the past year SHOM, DTU Space and Noveltis has corporated on updating altimetric data and on the use of these for gravity field modelling in the Northeast European shelf. The joint investigating har particularly focused on studying the effect on the use of SAR altimetry from the Cryosat-2 mission which is operating in SAR mode in the Northeast part of the Atlantic Ocean. In this presentation we investigate the effect of using SAR altimetry for marine gravity field modelling in comparison with RDSAR altimetry. We select CryoSat-2 altimetry products over a time interval of 6-years from October 2010 to December 2016 along the Northeastern coasts of the Atlantic Ocean. The ESA GPOD processors SARVatore was applied to retrack the 20 Hz Cryosat-2 SAR. The SAMOSA-2 (Ray et al., 2014) and SAMOSA+ SAR products have been evaluated in the presentation. They initially differ in the way the SAR waveforms are build (i.e. Hamming weighting window on the burst data prior to the azimuth FFT, zero-padding prior to the range FFT, doubling of the extension for the radar range swath) and in the retracking methodology. The Cryosat-2 waveforms were turned into conventional LRM like data and the RDSAR waveforms have been retracked by the RADS altimetry system and this dataset were also introduced into the validation in order to nvestigating the effect of using SAR altimetry using two near-similar datasets.