The motion field of northern Larsen Ice Shelf, Antarctic Peninsula, derived from satellite imagery

Abstract

The motion field of the northern Larsen Ice Shelf, Antarctic Peninsula, was analyzed, based on Landsat data from 1986 to 1989, Earth Resources Satellite (ERS) synthetic aperture radar (SAR) data from 1992 to 1997, and comparative field measurements along three transects. During this period the northern sections of the ice shelf showed steady retreat, which culminated in the disintegration of the two ice-shelf sections north of Seal Nunataks in January 1995. Velocities of these two sections were derived by cross-correlation, using SAR images of 1 year time intervals and Landsat images of 1-3 year intervals. A slight increase of velocity was observed as crevasses and rifts opened before the final disintegration. In addition, an interferometric motion analysis was carried out for the ice shelf around and south of Seal Nunataks, based on an image pair from the ERS- 1/2 Tandem Mission in 1995. This analysis reveals a complex pattern of tidal flexure in the grounding zones, as well as rifting and shear zones on the ice shelf. In addition, the motion of the main input glaciers was derived.