Dynamics of individual glaciers of the Munku-Sardyk massif (Eastern Sayan) and the Karlyktag range (Eastern Tien Shan)

Abstract

For more than ten years, the local features of the glaciation of individual mountain ranges of the inland part of Asia have been considered on the example of a transboundary transect from the latitudes of the middle taiga of the Baikal region, capturing the Mongolian Altai, to the Himalayas and are presented in the materials of the conferences “InterCarto. InterGIS”. The glaciers of the Eastern Tien Shan are interesting as part of this transect, located in the desert and semi-desert zones. The literature mainly considers the dynamics of glaciers of the central part of the Tien Shan, in the Urumqi region. In the northern part of the transect, the glaciers in the Eastern Sayan (nival-glacial objects of the Munku-Sardyk range) are the most studied. The dynamics of these glaciers is represented for more than 100 years. This paper considers changes in the glacier at the main peak of the Munku-Sardyk mountain range (Peretolchina glacier) and the little-studied glacier at the highest peak of the Karlyktag ridge of a similar northern exposure. Assessing the entire transect, it can be noted that the glaciers of the northern part of the transect (starting from the Kodar Range) are characterized by a significant decrease in thickness compared to their area changes and an increase in the rate of armoring by surface moraines. Moraine armoring of the lower part of the Karlyktag glacier also occurs, but not as significantly as that of the Peretolchina glacier. A comparison of the dynamics of the Karlyktag glacier and the Peretolchina glacier from Landsat remote sensing data shows that glaciers are shrinking to varying degrees. The open part of the Peretolchina glacier from the finite moraine of the Fernau stage decreased both in area and length by about half. The Karlyktag Glacier has decreased in length by about 25 %. It was significantly reduced in length in the early 1970s to 100 m/year. The decrease in area averaged at a rate of 0.03 km²/year. Over the past 20 years, the Peretolchina glacier has been shrinking in area at a rate of 0.005 km²/year, and for the entire observation period since 1900—0.004 km²/year. In terms of length over the same period, the glacier is shrinking at a rate of 5 m/year. Anomalous changes were revealed in the glaciers in question in 2013 and 2021. Similar processes were noted in the southern part of the transect (Himalayas) after the accumulation of a snow-ice mass, a catastrophic convergence of glaciers occurred in 2014 (in the area of Khumbu and Langtang).