The measurement of ice velocity, mass balance and thinning-rate on Johnsons Glacier, Livingston Island, South Shetland Islands, Antarctica

Authors

  • L. XIMENIS
  • JAUME CALVET I PORTA
  • J. ENRIQUE
  • J. CORBERA
  • C. FERNÁNDEZ DE GAMBOA
  • G. FURDADA

Abstract

A network of twenty stakes was set up on Johnsons Glacier in order to determine its dynamics. During the austral summers from 1994-95 to 1997-98, we estimated surface velocities, mass balances and ice thickness variations. Horizontal velocity increased down-stream from 1 m a-1 near the ice divides to 40 m a-1 near the ice terminus. The accumulation zone showed low accumulation rates (maximum of 0,6 m a-1(ice)), whereas in the lower part of the glacier, ablation rates were 4,3 m a-1(ice). Over the 3-year study period, both in the accumulation and ablation zones, we detected a reduction in the ice surface level ranging from 2 to 10 m from the annual vertical velocities and ice-thinning data, the mass balance was obtained and compared with the mass balance field values, resulting in similar estimates. Flux values were calculated using cross-section data and horizontal velocities, and compared with the results obtained by means of mass balance and ice thinning data using the continuity equation. The two methods gave similar results.

Downloads

Published

1999-01-13

Issue

Section

Articles