Glacier acceleration and thinning after ice shelf collapse in the Larsen B embayment, Antarctica

Abstract

Ice velocities derived from five Landsat 7 images acquired between January 2000 and February 2003 show a two‐ to six‐fold increase in centerline speed of four glaciers flowing into the now‐collapsed section of the Larsen B Ice Shelf. Satellite laser altimetry from ICESat indicates the surface of Hektoria Glacier lowered by up to 38 ± 6 m in a six‐month period beginning one year after the break‐up in March 2002. Smaller elevation losses are observed for Crane and Jorum glaciers over a later 5‐month period. Two glaciers south of the collapse area, Flask and Leppard, show little change in speed or elevation. Seasonal variations in speed preceding the large post‐collapse velocity increases suggest that both summer melt percolation and changes in the stress field due to shelf removal play a major role in glacier dynamics.