CONSTRAINING ICE SHEET MASS BALANCE TRENDS USING CRYOSAT-2 AND LASER ALTIMETRY

摘要

The uncertainty in the new Cryosat-2 data is assessed by comparing it to data from the NASA ICESat GLAS laser altimeter which operated between 2003 and 2009. We compare the spatial pattern of the differences; then compare the differences to instrument and geophysical parameters to attempt to determine their cause. Large proportions of the Cryosat-2 SARin data (i.e. those recorded over high slopes using an interferometric processing scheme to locate their ground position) are flagged as having an error in the across-track angle determination. We show that these data are likely not to be erroneous and use them in the remainder of our analysis. Further, a residual slope-dependent bias and indications of surface penetration in flat areas can be observed for both modes of the CryoSat-2 altimeter.