Author(s):
Mr. Tobias Bolch - Department of Geography, University of Erlangen-Nuremberg, Germany
Abstract:
DEMs and remote sensing data were used to analyse the retreat of the glaciers in Zailiskiy and Kungey Alatau, Northern Tien Shan. The climate varies from semi-humid to to semi-arid.
A DEM with 30 m resolution was generated with ASTER-Scenes and SRTM-Data. The accuracy of the DEM was evaluated by comparison with contour maps and field measurements.
Using Channel 4, 5 and the NDVI of a Landsat ETM-Scene from the year 1999 most of the glaciers could be automatically identified with high accuracy. Problems occur with debris or cloud covered glaciers. Using a cluster analyses including tangetial, vertical curvature and slope calculated from the DEM it was possible to delineate most of these covered glaciers. The morphometric analyses also helped to identify the little ice age moraines. The analyses were verified by field work in selected valleys.
Ice covered area and Equilibrum Line Altitude (ELA) were compared with data taken from the Glacier Inventory of the former USSR (1960s). The glaciated area decreases 35-40%. The ELA has risen over 70 m since 1960 and over 110 m since the Little Ice Age. The ELA shift of glaciers with high radiation input is much greater than glaciers with low radiation input.
Analyses also indicate an increase of glacial lakes; this combined with the concomitant melting of the permafrost and rock glaciers causing increasing mass movements and mudflows.
DEMs and remote sensing data are also used to visualize the results of the study.
