COMPARISON OF ENERGY BALANCE ON GANGOTRI AND CHHOTA SHIGRI GLACIERS

摘要

Surface energy balance of a glacier governs the physical processes taking place at the surface-atmosphere interface and connects ice ablation/accumulation to climate variability. To understand the response of Himalayan glaciers to climatic variability, a study was taken to formulate energy balance equation on two of the Indian Himalayan glaciers, one each from Indus and Ganga basins, which have different climatic and physiographic conditions. Study was carried out over Gangotri glacier (Ganga basin) and Chhota Shigri(CS) glacier from Chandra sub-basin (Indus basin). Gangotri glacier is one of the largest glaciers in the central Himalaya located in Uttarkashi District, Uttarakhand, India. Chhota Shigri glacier of Chandra sub-basin lies in Lahaul and Spiti valley of Himachal Pradesh. Energy balance components have been computed using inputs derived from satellite data, AWS (Automatic Weather Station) data and field measurements. Different components of energy balance computed are net radiation (includes net shortwave and net longwave radiation), sensible heat flux and latent heat flux. In this study comparison has been made for each of the above energy balance components as well as total energy for the above glaciers for the months of November and December, 2011. It is observed that net radiation in Gangotri glacier is higher by approximately 43% in comparison to Chhota Shigri glacier; Sensible heat flux is lesser by 77%; Latent heat flux is higher by 66% in the month of November 2011. Comparison in the month of December shows that net radiation in Gangotri glacier is higher by approximately 22% from Chhota Shigri glacier; Sensible heat flux is lesser by 90%; Latent heat flux is higher by 3%. Total energy received at the glacier surface and contributes for melting is estimated to be around 32% higher in Gangotri than Chhota Shigri glacier in November, 2011 and 1.25% higher in December, 2011. The overall results contribute towards higher melting rate in November and December, 2011 in Gangotri than Chhota Shigri glacier.