Teledetecção de mudanças nas bacias de drenagem do gelo da ilha Rei George, Shetlands do Sul, Antártica, entre 1956 e 2000

Abstract

This paper investigates morphological features of the ice cap and glaciers of King George Island (KGI), South Shetlands, Antarctica, mainly to determine variations in glacier front positions from 1956 to 2000, using maps produced from aerial photogrammetric surveys and satellite imagery. Glacier front positions were determined using three multispectral SPOT images taken in 1988, 1995, and 2000. These were compared to their positions in 1956, determined from the aerial photographs. A new digital topographic database, as a basic Geographic Information System (GIS)-layer for environmental monitoring, improves data quality derived from previous studies. Seventy ice drainage basins were identified, covering 1044 km 2 (91.5%) of the KGI present area. General glacier retreat has been observed for 44 years, more intensely in Admiralty Bay and the eastern side of the island. Relatively small ice masses with subpolar to temperate thermal regime, the case for the South Shetland Archipelago, may respond rapidly to changes in atmospheric temperature. Therefore, changes observed in KGI may be related to an increase in temperature, recorded in this region during the last 5 decades.