Glacier changes in Upper Tons River basin, Garhwal Himalaya, Uttarakhand, India

摘要

We estimate the spatial changes in the Jaundhar, Jhajju and Tilku glaciers in the Tons River basin (Garhwal Himalaya) between 1962 and 2010 using Landsat Satellite data, topographic maps along with field surveys. We estimate the overall shrinking in the area of the glaciers to be ~ 3.6 km~2 (5.4% of total area) and ~ 1,709 m, ~ 800 m and ~ 700 m of frontal retreat (snout) with an average of 34.18, 15.38 and 13.46m a~(-1) for the Jaundhar, Tilku and Jhajju Glaciers respectively. However, frontal retreat rates are not uniform in all glaciers even under the same climatic domain. The Jaundhar Glacier (55 km~2) has been separated into two parts; North Jaundhar (40 km~2) and South Jaundhar (15 km~2) between 1975 and 1990. Study on these fragmented glaciers shows a continuous and unusual retreat of glaciers after 1990. Compared with the regional mean of glaciers retreat in the Uttarakhand Himalaya, the glaciers show heterogeneous retreat rates. This uncertainty may possibly be due to size, surface morphology and gradient of the individual glaciers and can be attributed to degeneration and rapid melting on the glaciers. Meteorological data available from this region show increasing summer temperature and less winter precipitation in last few decades. Further more studies on these glaciers will shed light on several factors influencing changes and retreat on the Himalayan glacier systems.