Temporal changes in rate of recession: evidences from Satopanth and Bhagirath Kharak glaciers, Uttarakhand, using Total Station Survey.

摘要

Snouts of Satopanth and Bhagirath Kharak glaciers, located at the head of the Alaknanda valley in Chamoli District, Uttarakhand, were monitored using Total Station Survey. Retreat of the snouts and area vacated by recession of the glaciers were estimated for 44 years by way of superimposing the Survey of India toposheet of 1962 on the map prepared by Total Station Survey in 2006. The total area vacated by the Satopanth and Bhagirath Kharak glaciers during 44 years was 313,923.14 sq. m (0.314 sq. km) and 129,369.16 sq. m (0.13 sq. km) respectively. The annual average retreat of the snout of the Satopanth glacier between 1962 and 2005 (43 years) was estimated as 22.88 m/yr, whereas retreat was low (7.42 m/yr) for the Bhagirath Kharak glacier. Interestingly, actual field measurements for the year 2005-06, showed an estimated retreat of 6.5 and 1.5 m/yr for the Satopanth and Bhagirath Kharak glaciers respectively. Snouts of the Satopanth and Bhagirath Kharak glaciers recorded continuous recession for the past four decades, with decline in recession of both cases. Both glaciers are situated in the same basin and experience similar climatic conditions. However, different recession rates of glaciers are attributed to unequal distribution of tributary glaciers, active cirques, drainage characteristics, density and distribution of supraglacial debris over the glacier surface.