DYNAMICS OF MOUNTAIN PERMAFROST OF THE NORTHERN TIEN SHAN BASED ON THERMOMETRIC OBSERVATIONS AT TWO KEY SITES
L.S. Lebedeva1, M.N. Zheleznyak1, V.V. Goncharenko1,2, V.P. Kapitsa2
1Melnikov Permafrost Institute, Siberian Branch of the Russian Academy of Sciences, Yakutsk, Russia
2UNESCO Category 2 Central Asian Regional Glaciological Centre, Almaty, Kazakhstan
Keywords: Northern Tien Shan, mountain permafrost, permafrost temperature, climate change, statistically significant trend, air temperature, active layer thickness
Abstract
Under the observed climate warming in the highlands of Central Asia, studies of the thermal state and dynamics of permafrost have become particularly relevant. This paper presents the results of rock temperature monitoring at two key sites in the northern Tian Shan: Zhosaly Kezen Pass and a west-facing slope near Bolshoye Almatinskoye Lake. At the high-mountain pass, a statistically significant increase in mean annual permafrost temperatures was observed: from 0.13 °C/decade at the base of the active layer (5 m depth) to 0.06 °C/decade in the lower part of the section (25 m depth). Particularly noticeable changes occurred after 2010, when the active layer thickness consistently exceeded 5 m. The results indicate permafrost degradation through both the thickening of the active layer and the upward shift of permafrost base. These processes occur against the background of increasing mean annual air temperature (0.30 °C/decade). In the intra-annual dynamics, the most intensive rock warming occurs during summer months (up to 0.89 °C/decade) in the upper layers (1-2 m) and correlates with April-July air temperature rise (up to 0.80 °C/decade). Near Bolshoye Almatinskoye Lake, mean annual temperatures in seasonally frozen layers (to a depth of 3 m) remain stable, while at depths of 5.0-9.8 m, they show a warming trend of 0.31-0.35 °C/decade. These trends align with data on temperatures of thawed rocks and permafrost from other areas of Asia’s mountain permafrost.
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