3.4-Computation and reconstruction of the mass balance and glacier runoff in the Akshiyrak glacier system -Tien shah

Abstract

The Akshiyrak mountain-glacier system in the Tien Shan, consists of 178 glaciers. The comparison of two topographic surveys of 1943 and 1977 has permitted to obtain graphic and numerical data on the area, volume and altitude of the surface changes for each glaciers. Akshiyrak has lost 3.566 km3 of ice during between surveys period. Annual net mass balance was -25.6 gri cm2 The mass balance computation of the western part cf the Akshiyrak with the area 125 km2 was carried out. Altitudinal distribution data of the glacierization of this part of the range are used. The Sary-Tor glacier data combined with the data of the direct Sary-Tor mass balance measurements are included in this investigation. The computational results are compared with the survey data. It is established that the changes of the glacier volume is related to its surface altitude change. The fronts of the glaciers hardly changed during the observation period.