Spatial patterns in glacier characteristics and area changes from 1962 to 2006 in the Kanchenjunga–Sikkim area, eastern Himalaya

摘要

This study investigates spatial patterns in glacier characteristics and areachanges at decadal scales in the eastern Himalaya – Nepal (Arun and Tamorbasins), India (Teesta basin in Sikkim) and parts of China and Bhutan – basedon various satellite imagery: Corona KH4 imagery, Landsat 7 EnhancedThematic Mapper Plus (ETM+) and Advanced Spaceborne Thermal EmissionRadiometer (ASTER), QuickBird (QB) and WorldView-2 (WV2). We compare andcontrast glacier surface area changes over the period of 1962–2000/2006 and their dependencyon glacier topography (elevation, slope, aspect, percent debris cover) andclimate (solar radiation, precipitation) on the eastern side of the topographic barrier (Sikkim)versus the western side (Nepal).Glacier mapping from 2000 Landsat ASTER yielded 1463 ± 88 km2total glacierized area, of which 569 ± 34 km2 was located inSikkim and 488 ± 29 km2 in eastern Nepal. Supraglacial debriscovered 11% of the total glacierized area, and supraglacial lakes coveredabout 5.8% of the debris-covered glacier area alone. Glacier area loss (1962to 2000) was 0.50 ± 0.2% yr−1, with little difference betweenNepal (0.53 ± 0.2% yr−1) and Sikkim (0.44 ± 0.2% yr−1.Glacier area change was controlled mostly by glacier area,elevation, altitudinal range and, to a smaller extent, slope and aspect. Inthe Kanchenjunga–Sikkim area, we estimated a glacier area loss of 0.23± 0.08% yr−1 from 1962 to 2006 based on high-resolutionimagery. On a glacier-by-glacier basis, clean glaciers exhibit more arealoss on average from 1962 to 2006 (34%) compared to debris-coveredglaciers (22%). Glaciers in this region of the Himalaya areshrinking at similar rates to those reported for the last decades in otherparts of the Himalaya, but individual glacier rates of change vary acrossthe study area with respect to local topography, percent debris cover orglacier elevations.