| Summary: | The newest DTU global high-resolution global marine free air gravity field called DTU21 is presented in this presentation and the first evaluation against marine and airborne gravity is performed. A total of 14 years from geodetic missions including (7 years of Cryosat-2 (369 days repeat mission) as well as 3 years of Jason-1+2 end-of-life missions and 4 years of SARA/AltiKa drifting geodetic mission). Older geodetic missions (ERS-1 and GEOSAT) are now nearly retired. All Geodetic missions have been fully retracked using the 2-pass retracker developed by Sandwell and Smith, (2005) to increase the range precision. Subsequently, we derive 2-Hz altimetric observations from the 20/40 Hz retracked data using the Parks McClellan filter to avoid spectral leakage degrading the 10-40 km wavelength which is an effect of the box filter normally used to compute 1 Hz data. In the Arctic Ocean, we will present results from several new developments in high-resolution gravity field modelling. One is a new dual-pass retracking of SARAL/AltiKa together with a new physical retracking system for Cryosat-2 derived at ESA called SAMOSA+. This was retracked using the ESA GPOD service. A new medium wavelength correction based on altimetry and GOCE has been introduced to deal with problems in the older remove restore technology based on EGM2008. This is particularly important for Cryosat-2 due to its ability of provide new accurate sea surface height information for gravity field determination all the way up to 88N where no altimeters have measured before.
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