DUAL-FREQUENCY ALTIMETER OF ENVISAT ABOVE THEANTARCTICA ICE SHEET

摘要

The dual-frequency altimeter of Topex allowsrnsince few years the observations of earth from 62°Nrnto 62°S both in Ku and in C band. Previous worksrnhas been already performed above continental areasrnby [1, 2, 3, 4] and above the southern part of thernGreenland ice sheet [5, 6]. These works show therngreat interest of a dual-frequency above both for thernretrieval of some geophysical parameters and for arnbetter understanding of the physics of the measure.rnThe RA2 altimeter on board ENVISAT allows forrnthe first time such observations over the polarrnregions, up to 82°N and 82°S. The low frequency ofrnthe RA2 is lower than the one of Topex (S band,rn3.6 GHz) also allowing a complementaryrnobservation of the continental area. This lowrnfrequency induces a greater penetration capabilityrnand a greater robustness of the waveform than thernku and C bands. These new characteristics are veryrnpromising for the study of polar regions, especiallyrnice sheets.rnThe paper is devoted to this new observation ofrnboth Ku band and S band over the Antarctica icernsheet.