ИСТИНА

Mountain glaciers on the Earth are very sensitive to climate change, dynamically responding to changes in circulation or radiation balance. Climate fluctuations determine parameters of external mass turnover of glaciers. Mass balance (bn) is the most important indicator of glacier evolution. Its direction is characterized by long mass balance series. After the decay of the USSR all direct bn measurements in the Inner Tien Shan, including the Sary-Tor Glacier in Ak-Shiyrak Massif monitored in 1985-1989, were desisted. Observations there were resumed only since 2015. The presented contribution deals with restoring continuity of bn series and prolonging it back to the beginning of regular observations at Tien Shan weather station (3660 m a.m.s.l.) in 1929. Accumulation was reconstructed by linear relationship with precipitation sum and air temperature, whereas restoring of ablation was based on its dependence on temperature or on two-parameter linear approximation by air temperature and wind velocity. Direct instrumental measurements in 1984/85-1988/89 and 2014/15-2018/19 reveal reference glacio-meteorological equations which are assumed independent on time. Thereby, calculations result in deriving continuous 90-year-long series of annual values of bn and its constituents. Reconstruction for the Sary-Tor Glacier demonstrates a dominant trend towards mass loss with only rare and brief episodes of its deceleration. Comparison with long bn series for a number of glaciers in Asia discerns their relative synchronism, less pronounced in the recent time: Sary-Tor degradation tends to proceed more intensively. Conclusions on its anticipated evolution are particularly topical for evaluating influence of Kumtor Gold Company, Canada, over the local eco-systems, in view of its interests to expand gold-mining activity to the periglacial zone adjacent to the Sary-Tor terminus. Investigation within the framework of State Assignment AAAA-A16-116032810095-6 was also supported by project 20-05-00681a of Russian Foundation of Basic Research.