Recent advance of the grounding line of Lambert Glacier, Antarctica, deduced from satellite-radar altimetry

Abstract
Satellite radar-altimeter data from Seasat (1978) and the Geosat Exact Repeat Mission (1987–89) are evaluated to investigate the question of advance or retreat of Lambert Glacier, Amery Ice Shelf, East Antarctica. New maps based on a fine-scale 3 km grid arc calculated using ordinary kriging. The break in slope at the 100 m elevation contour, relative to the WGS 1984 ellipsoid, is taken as a proxy for the grounding line. Measurements indicate that the irregular grounding line, which includes shoals, advanced approximately 10km between 1978 and 1987‐89, corresponding to a mean advance rate of about 1000 m year-1.