International Geologiical Congress - Oslo 2008

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AAA-08 Permafrost on a warming planet

 

Monitoring of glacial landforms in Western Tien Shan using RS GIS

 

Yelena Sidorova, Institute of Geology and Geophysics (Uzbekistan)
 

 

Glaciers are of great significance considering their active role, first of all, in water resources. Monitoring of glaciers can provide the basis to understanding interrelations between glaciers, climate and water resources. Glaciers in Middle Asia are mainly developed in the Tien Shan's high mountains at the mid-low latitudes. At present time in the Middle Asian High Mountains - 14752 glaciers, the total area 15761km2. In our study , satellite images, topographical maps were integrated into a glacier inventory system to extract glaciers changes in the Western Tien Shan, especially in Tekeshsai, Barkrak (middle and left), Lakely glaciers with a total area of 38.8km2 were digitized and analyzed. We applied the ASTER images for visual interpretation and classification of glaciers. Glacier tongues with debris-covers were manually delineated from satellite images with the aid of DEM. Results indicated that glaciers Tekeshsai, Barkrak, Lakely have retreated from 1985 to 2006 with a total area reduction of 7.9km2, 16.8 % of the area during the last 20 years. However, there are different types of glaciers, classified as maritime, based on the precipitation amount and air temperature combination. At the same time, most of glaciers in Western Tien Shan have lost substantial volumes of ice. Mountain permafrost and associated periglacial landforms contain large quantities of belowground ice. The moraines, rock glaciers and other coarse blocky materials have especially high ice content - more than 50% by volume. Coarse blocky debris of various origins is widespread in the Tien Shan and occupies large areas of high-mountain territory. Under continuing warming of permafrost and glacier regression in Tien Shan, the melt waters from thawing permafrost could become an increasingly important source of fresh water. Further analysis revealed that regional warming during the past decades could be the consequences of this large scale ice mass wastage.

 

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