Лëд и снег (Nov 2020)
Degradation of glaciers in the northern part of the Middle Range on Kamchatka Peninsula along the period from 1950 over 2016–2017
Abstract
The Northern part of the Sredinny (Middle) Range is the largest glaciation area in Kamchatka in terms of the numbers and areas of glaciers. As of 2016–2017, there were 465 glaciers in this area with a total area of about 255±17 km2. Amongst the morphological types, the cirque (corrie), slope, and corrie-valley glaciers predominate (64%), but more than half of the total area (54%) is covered by the corrie-valley and transaction glaciers. The average area of glaciers over this region is 0.55 km2, while for the transection ones it is 8.3 km2. The main part (77.4%) of the glaciers in the region is located in the altitude range of 1200–1800 m. The firn line on both slopes of the Central Range lies within the altitude range of 880–1910 m. Analysis of changes in the size of the recent glaciation in comparison with the data of the mid-twentieth century indicates that the trend towards its reduction, established in the second half of the twentieth century, remains at the present time. The loss of the area of glaciers in the region registered in the USSR Glacier Inventory (1950), by 2016–2017 amounts to almost 125 km2 (35.6%). Note, that losses for the first 15 years of the twenty-first century turn out to be approximately equal to the total sum of losses for second half of the twentieth century. It means that at the beginning of the twenty-first century the rate of reduction of glaciers is 4.3 times greater, i.e. about 1.45% of the area per year. The glaciers of the South-Eastern (62.9%) and Southern (43.6%) exposures reduced the most (significantly more than others). Loss of the total area was the greatest in small glaciers with sizes smaller 0.1 km2 (> 70%) and the smallest in large glaciers exceeding 5 km2 (< 11%). The process of disintegration of large glaciers into smaller ones did also accelerate, that increased total number of glaciers. The increase in the rate of glaciers area reduction in the region at the beginning of the twenty-first century was mainly caused by the rise in summer air temperatures, that also intensified in these years. Similar values of the relative reduction of glacier areas are observed in the North Chui Range (Altay), in the Bernese and Pennine Alps, in the Polar Ural, in the Nordenskjold Land (Svalbard), etc.
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