Abstract
Glacier area and length changes were measured in the central Trans Alai of the northeastern Pamir, including the entire catchment of Lake Karakul. Annual shrinkage determined from Landsat 7 ETM+ imagery accounted for −0.8 ± 0.4 % a⁻¹ , corresponding to −8.8 ± 4.8 % from 1455 ± 51 km² in 2000 to 1327 ± 48 km² in 2011. Several glaciers could be mapped back to 1973 based on a KH-9 Hexagon reconnaissance image. Measured glacier extents of 550 ± 10 km² in 1973, 540 ± 9 km² in 2000, and 521 ± 9 km² in 2011 indicate accelerated shrinkage for the last decade in the Trans Alai. Glaciers retreated on average by −4.3 ± 0.5 m a⁻¹ before 2000 and subsequently advanced by +6.1 ± 1.0 m a⁻¹ until 2011. Geodetic mass balances of four selected glaciers were determined from a Digital Elevation Model extracted from a 2010 ALOS-PRISM tri-stereo image and the February 2000 SRTM-3 elevation dataset (1999). Its difference image reveals highly variable glacier elevation changes. While three glaciers showed probably a minor loss (−0.16 ± 0.68 m w.e. a⁻¹ to −0.06 ± 0.68 m w.e. a⁻¹), a more pronounced mass loss was observed for Ujsuu Glacier (−0.50 ± 0.68 m w.e. a⁻¹). This study reveals significant glacier variations and numerous indications of surges in the Trans Alai, a well-known phenomenon in the Pamir.
Holzer, Nicolai