Glacier characteristics and changes in the Sary-Jaz River Basin (Central Tien Shan, Kyrgyzstan) – 1990–2010

The water discharge from the heavily glacierized Sary-Jaz River Basin (Eastern Kyrgyzstan) is of high importance for the very arid Tarim Basin located in Xinjiang (north-western China). We investigated glacier changes in the entire Sary-Jaz River Basin, which covers a large part of the Central Tien Shan, for the period from 1990 to 2010 based on Landsat ‘TM’/‘ETM+’data. We found 1310 glaciers (>0.1 km²), which covered 2055 ± 41.1 km² (∼18% of the entire basin) in 1990. The glaciers shrank by 77.1 ± 57.1 km² (3.7 ± 2.7%) until 2010. This is considerably lower than in most other ranges of the Tien Shan. The lowest insignificant area loss (−1.5 ± 2.7%) was found in the eastern part of the basin where the largest glaciers and highest peaks are situated. Debris-covered glaciers shrank significantly less than clean-ice glaciers of comparable size. We also identified a few advancing glaciers which show surge characteristics. Climate data from the Tien Shan weather station (3614 m asl.) close to the study region showed no significant long-term trend.