Snow and glacier cover assessment in the high mountains of Sikkim Himalaya

This study highlights the assessment of snow and glacier cover for possible inferences of global climate change impacts in high mountains like the Himalaya. The test catchment of the River Tista lies in the Sikkim state of the Indian Himalayan region, with steep mountains crossing nearly all ecozones, from subtropical to glacial. River flows are highly fluctuating, especially during the peak rainy season and snowmelt periods. Annual rainfall patterns are non-uniform and can cause large floods. Runoff and discharge downstream are highly dependent upon snow and glacier extent. The temporary storage of frozen water brings about a delay in seasonal runoff. Snow cover built up in the higher regions during the winter months melts in the spring-summer-autumn cycles and contributes to groundwater recharge. A spatial baseline inventory of snow cover/glacier, the permanent snowline and its short-term temporal changes in the remote high-mountain areas have been analysed using multidate Indian Remote Sensing Satellite data of 1992 to 1997. A geographic information system-based overlay has led to inferences on snow cover characteristics and the alignment, dimension, slope disposition, heights of the snout and associated features of each of the glaciers. Snow and glacier recession are to be monitored in future on a long-term basis to derive correlations with climate-change parameters. Copyright (c) 2005 John Wiley & Sons, Ltd.