Observations of the surface properties of the ice sheets by satellite radar altimetry

摘要: By comparing modelled and averag ed satellite altimeter return, it is demonstra ted that time profiles of return can be used to provide important information on the surface proper ties ice sheets. Alt imeter ice-sheet radar echoes from low altit udes and/or rela tively latitudes are, in gene ral, domin ated by scat tering and, Greenl area surface-d ominated broadly coi ncides with zone summer melting . Seasonal variations echo wave-form shapes are negligible all regions studied, possib le exception an near margin Greenland dry-snow zone. In general, model expla ins well observed mean wave- form shape, but small discrepances between wave forms recorded indicate sub-sur face layers may influ encing shape return. The poss ibility deriving quantitative estima tes explored fitting returns averaged Wilkes Land plateau Anta rctica. Surface roug hness meas ured unambig uously data, estim ations other parameters, such as gra in-size, snow density, temperature found ambiguous because different para meters have a similar infl uence retur n. Despite this, derived estimates compare ground-b ased observations suggest alti meter role play providing info rmation properties