Study of Lange Glacier on King George Island, Antarctica

The results of ground-based radio-echo sounding collected in 1995 and 1996-97 in the drainage basin of Lange Glacier, a tidewater outlet glacier on King George Island, Antarctica, are presented and discussed. Ice-thickness and bedrock-elevation maps, constructed for the upper non-crevassed part of the glacier, show a close relation between its surface and subglacial topography and indicate the main directions of ice runoff from this area where the ice thickness reaches 308 m. A retreat of the glacier front by 1 km since 1956 occurred against a background of climate warming by 1.4 degrees C on the South Shetland Islands during the last five decades, while a neighboring unnamed glacier advanced by 0.6 km and the northern ice-cap margin on King George Island was approximately stationary. To understand the reasons for the different responses of these ice masses to current climate warming in this region of West Antarctica, further studies including mass-balance and ice-velocity observations and numerical modeling are needed.