Abstract

The analysis of satellite images revealed by 25% decrease of the Altai mountains’ glaciation area over last 50 years. In 2008–2017, deglaciation rate increased twice. This tendency is in good agreement with an observed increase in the Katun River flow by 9% in 2008–2017 as compared to 1940–1968 (under invariable total precipitation). The analysis of trends of main meteorological parameters based on weather station data and the ERA-Interim reanalysis demonstrated that statistically significant warming in the region occurs only during the warm season and does not exceed 0.5°С/10 years. For this reason, “atmosphere–glaciers” turbulent heat transfer has increased by 4 W/m² in last two years, that caused an annual melting layer increase by 100 mm water equivalent (w.e.). However, the main reason for the Altai mountains’ deglaciation is an increase of downward solar radiation flux, which amounted to 5 W/m² per decade and increased the melting layer by 365 mm w.e. per year. A positive trend in net radiation agrees well with a decrease in cloud amount, which is associated with an increase in the moisture divergence flux and geopotential height and with the weakening of zonal winds in the middle troposphere.

中文翻译：

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阿尔泰山脉的现代冰川消融：影响和可能的原因

摘要

卫星图像分析显示，过去50年中，阿尔泰山脉的冰川面积减少了25％。在2008–2017年，冰消速率增加了两倍。这种趋势与观察到的卡吞河流量在198.0-1968年相比（在不变的总降水量下）相比在2008-2017年增加了9％很好地吻合。根据气象站数据和ERA-Interim再分析对主要气象参数趋势进行的分析表明，该地区的变暖具有统计意义，仅发生在暖季，且不超过0.5°С/ 10年。因此，“大气-冰川”湍流传热增加了4 W / m ²在过去的两年中，这导致每年的融化层增加了100毫米水当量（我们）。然而，阿尔泰山脉冰消的主要原因是向下的太阳辐射通量增加，每十年减少5 W / m ²，并使融化层每年增加365 mm。净辐射的正趋势与云量的减少非常吻合，这与湿度发散通量和地势高度的增加以及对流层中层纬向风的减弱有关。