Melting ice sheets and ice caps have a large societal importance due to their associated contribution to global eustatic sea level changes. In the past, mass balance estimates for the Antarctic and Greenland Ice Sheets, as well as for Arctic ice caps, have suffered from large inaccuracies, introduced by a number of factors: too short measurement periods to establish a long-term trend; errors in modelled corrections; instrument inadequacies, and systematic errors in the measurements (e.g., radar penetration into snow on the ice sheets).

In the ICEMASS project, surface elevation changes from the two ESA radar altimetry missions CryoSat-2 and Envisat, are used together with mass changes obtained from the Gravity Recovery and Climate Experiment (GRACE) to obtain a more reliable estimate of overall mass changes of both Greenland, Antarctica, and the minor ice sheets (especially Arctic ice caps in Iceland, Svalbard and Canada). Newly available models of crustal uplift and glacial isostatic adjustment are used to provide more accurate results. In order to better understand penetration of the radar altimeters, the results from the CryoSat validation campaigns in Greenland, Svalbard and the Canadian Arctic (CryoVEx) will be used along with results from the NASA IceBridge mission in Greenland and Antarctica.

The first results have been obtained, which consist of rates of surface height change for the Greenland Ice Sheet obtained from Envisat. In this novel approach, data were analysed along-track, which results in a higher amount and density of data, allowing analysis of surface height changes right to the margins of the ice sheet.