Glacier changes in the central and northern Tien Shan during the last 140 years based on surface and remote-sensing data

Abstract This research presents a precise evaluation of the recession of Akshiirak and Ala Archa glaciers, Tien Shan, central Asia, based on data of geodetic surveys from 1861–69, aerial photographs from 1943, 1963, 1977 and 1981, 1:25000 scale topographic maps and SRTM and ASTER data from 2000–03. The Akshiirak glacierized massif in the central Tien Shan contains 178 glaciers covering 371.6 km2, and the Ala Archa glacier basin in the northern Tien Shan contains 48 glaciers covering 36.31 km2. The Tien Shan glaciers retreated as much as 3 km from the 1860s to 2003. Area shrinkage of Akshiirak and Ala Archa was 4.2% and 5.1%, respectively, from 1943 to 1977, and 8.7% and 10.6%, respectively, from 1977 to 2003. The volume of the Akshiirak glaciers was reduced by 3.566 km3 from 1943 to 1977 and 6.145 km3 from 1977 to 2000. The total reduction of the Tien Shan glaciers is 14.2% during the last 60 years (1943–2003). The northern and central Tien Shan have not experienced a significant precipitation increase during the last 100 years, but they have experienced an increase in summer air temperatures, especially observable since the 1970s, which accelerated the recession of the Tien Shan glaciers.