STUDY OF SIKKIM HIMALAYAN GLACIERS USING SATELLITE DATA ON ARC GIS

Abstract

Snow is an important part of the cryosphere, and the study on snow trends is essential to understand regional climate change and managing water resources. Detailed information about snow cover in space and time is must to assess water discharge, understanding and mitigating snow disasters, and analysing climate change. In the cryosphere, snow is the component that changes most promptly with the seasons. Due to the feedback effects these changes occur and their impact are seen on surface energy and atmospheric processes. Thus, snow is an important focus for research into climate change and adaptation. Permanent snow fields and glaciers located in high altitudes of Himalayan mountain chains are very important natural resources of frozen fresh water for India‟s development, planning and growth. Glaciers are formed due to recrystallization and metamorphism of naturally fallen snow on land surface. It is permanent snow cover which gives rise to formation of glaciers. Glaciers are formed when rate of gathering of snow is more than rate of ablation and dropping snow gets enough time and space to get metamorphosed to form ice. Sometimes glacier is also referred as movement of glacier ice under the impact of gravity. The glaciers are mass of snow, ice, and water and rock remains slowly moving down a slope. Out of these ice is an essential component. Presently, ice is distributed either in Polar Regions earth or in high mountainous regions. Two parts of the glaciers are: gathering zone and ablation zone parted by snow line. In the gathering zone the total accumulation from winter snowfall is more than the summer ablation. In ablation zone, total summer melting is more than the winter snow accumulation. Debris cover on the ablation zone of glaciers is ubiquitous throughout the Himalaya. As a consequence, the production of meltwater decreases, instead of increasing, with the decrease in elevation. Therefore, glacier ice along with rock remains (debris) gets exposed on the surface during summer. The frontal most part of ablation zone of the glacier from where river or stream appears on the surface is its terminus or snout.