Лëд и снег (May 2022)
Reduction of glaciers in the Ulakhan-Chistay Range (Chersky Mountains) from 1970 to 2018
Abstract
The paper presents new data on the state of glaciers of the Ulakhan-Chistay Ridge (Chersky mountains) in 2018. Estimates of changes in the glaciation obtained in this region over the period 1970-2018 are based on the analysis of different in time satellite surveys and historical data. In 2018, the glaciation of this area was represented by 90 glaciers with a total area of 54.0±5.2 km2. Among the morphological types, corrie and valley glaciers predominate. The largest areas are occupied by valley and compound valley glaciers. The main part (67.5%) of the total glaciation area is concentrated within the altitude range 2000–2400 m. The changes in the glaciation area were analyzed over following four periods: 1970–2018, 1970–2001, 2001–2012, and 2012–2018. For 1970–2018, the area local glaciers registered in the USSR Glacier Catalog and identified on the present-day satellite images decreased from 82.2 to 53.9±5.2 km2, that is by 28.3 km2 (34.4%). In this value, 12.4 km2 were lost in 1970–2001, 8.4 km2 – in 2001–2012, and 7.5 km2 – in 2012–2018. By 2018, small glaciers with an area of less than 0.1 km2 (73%) had shrunk the most, and the least – large glaciers with an area exceeding 2 km2 (17%). The glaciers of the north-eastern exposure decreased the most significantly (49.3%). The average rate of area reduction increased from 0.49%/year in 1970–2001 to 1.34%/year in 2001–2018 (1.09%/year in 2001–2012, 2.04%/year in 2012–2018). Glaciers shrank against the background of a gradual rising in summer air temperatures (about 1.5 °C over the past 50 years) with a slight change in the winter precipitation. The more intensive shrinking of glaciers over the past two decades was caused by the stable positive anomaly of summer air temperatures, which remained since 2005 to the present.
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