Ice flow and mass continuity of Shumsky Glacier in the Djungarski Alatau Range of Kazakhstan, Central Asia

Abstract

The glaciological monitoring program on the Shumsky Glacier in the Djungarski Alatau Range of southeastern Kazakhstan has included measurements of horizontal surface ice flow velocity, net balance, and emergence velocity at a network of more than 200 stakes during 1967–1991, as well as mappings of the ice surface topography by double‐theodolite triangulation and determination of ice thickness and of bedrock topography by radio echo sounding in 1984. These observations are here evaluated together to deduce the long‐term average dynamic behavior of Shumsky Glacier. The glacier extends between 3100 and 4400 m with a total area of 3 km2 and length of nearly 4 km. Maximum surface velocity is 20 m yr−1 and maximum volume flux 9 × 105 m3 yr−1, located near the equilibrium line altitude around 3680 m. The ice‐volume‐equivalent net balance is +0.5 m yr−1 in the average over the accumulation area, changing to about −1.5 m yr−1 near the terminus. The submergent flow in the accumulation area changes to emergence of 1 m yr−1 in the lower glacier. The rate of ice thinning is less than 0.1 m yr−1 in the middle glacier, increases to 2.5 m yr−1 near the terminus, and averages 0.12 m yr−1 for the glacier as whole. In fact, the Shumsky glacier differs little from equilibrium, being in a more favorable location that the other glaciers of the Djungarski Alatau. However, trends toward slower ice flow, more negative net balance, and faster rate of ice thinning indicate response to a progressively adverse climatic environment.