Variations in surface velocities of tidewater glaciers of the Antarctic Peninsula between the periods 1988-1991 and 2000-2003

Abstract

In the Antarctic Peninsula, recent events of glacier retreat, disintegration and break-up of ice shelves indicated that ice masses in this region are reacting rapidly to the increasing trend in oceanic and surface air temperatures. This study aimed to define variations in ice flow velocity of tidewater glaciers between the periods of 1988-1991 and 2000-2003, in northeastern, northwestern and midwestern Marguerite Bay and Larsen C ice shelf sectors. Glacier velocities were estimated by the application of a cross-correlation algorithm of IMCORR software in multitemporal LANDSAT TM/ETM+ images. Moreover, we used monthly mean oceanic and air temperature data from OCCAM and ERA-Interim models, respectively. Ice flow velocities on the northeastern sector was 0.24 ± 0.12 md-1 in the period 1988-1991, while in 2000-2002 it was 0.06 ± 0.02 md-1. In the northwestern part of the peninsula, the mean glacier velocity was 0.10 ± 0.005 md-1 between 1989 and 1990, and 0.22 ± 0.13 md-1 between 2000 and 2001. In the Midwestern sector, the mean velocity of glaciers was 1.06 ± 0.86 md-1 in the period 1989-1991, and 0.84 ± 0.78 md-1 in the period 2000-2001. In Marguerite Bay, the velocity was 1.28 ± 0.77 md-1 in the period 1988-1989, characterized by temperatures near 0°C in the Bellingshausen Sea, while in the period 2000-2001, with mean ocean temperatures close to-2°C, the mean glacier velocity was significantly lower, of 0.23± 0.12 md-1. Finally, in Larsen C ice shelf, the mean velocity ranged from 0.80± 0.20 md-1, between 1988 and 1989, to 0.15 ±0.10 md-1, between 2000 and 2003. The higher speed of flow of tidewater glaciers between 1988 and 1991 occurred in a period when the mean surface air and sea temperatures also were higher.