Using the temporal variability of satellite radar altimetric observations to map surface properties of the Antarctic ice sheet

The problem of measuring surface height and snowpack characteristics from s atellite radar altimeter echoes is investigated. In this paper, we perform an analysis of the ERS1 altimeter dataset acquired during a 3 day repeat or bit. The analysis reveals that there are temporal variations in shapes of t he radar altimeter echo and that these variations are linked to meteorologi cal phenomena. The time- and space-scales over which these variations apply are a few to tens of days and a few hundred kilometres, respectively. This phenomenon, if not accounted for, can create error in the height measureme nt. A numerical echo model is used to recover snowpack characteristics by t aking advantage of the temporal variations of the radar echoes, A map of pe netration depth of the radar waves in the Ku band over the;Antarctic contin ent is obtained and suggests that grain-size produces the dominant effect o n radar extinction in the snowpack at this frequency. Finally, a procedure is proposed to correct the height measurement within the contest of ice-she et mass-balance survey.