DIGITAL ELEVATION MODELS FROM GROUND-BASED GPS AS VALIDATION FOR SATELLITE ALTIMETRY ON THE GREENLAND INLAND ICE

摘要

A long-term geodetic project on the Greenland inland icernis performed in order to determine elevations, elevationrnchange, flow velocity, and deformation of the ice surfacernin the western part of the Greenland ice sheet. There arerntwo main research areas: Swiss Camp (ETH/CU-Camp)rnwhich was started in 1991, and ST2, started in 2004. Untilrn2008 a total of 10 measuring campaigns were carried outrnat Swiss Camp. The 3D-coordinates of the snow and icernsurfaces were measured by ground-based static andrnkinematical GPS survey. As a result very precise digitalrnelevation models of the research areas are available.rnThe digital terrain models can be used as ground controlrnareas for satellite altimetry. As an example, they werernused for validation of ICESat satellite elevation data.rnHeight comparisons along one track show in average arndiscrepancy of 0.13 m ± 0.06 m.rnDue to their very high accuracy, the measured areas canrnalso be used as control areas for CryoSat. The next fieldrnmeasurements are planned in summer 2011. The locationrnof the ground measurements will be coordinated withrnpredicted tracks for CryoSat.