The following work represents data on the state of the of Bolshevik Island glaciers (Severnaya Zemlya archipelago) in 2020. Estimates of area changes obtained for the period 1953–2020 are based on the analysis of multi-temporal space images and data from the USSR Glacier Catalog. Changes in glaciation area were analyzed over the following five periods: 1953–1973, 1973–1985, 1985–1996 , 1996–2010 and 2010–2020. From 1953 to 2020 it decreased from 3454.1 to 2557.37 square kilometers, i.e. by 896.73 square kilometers (25.96 %). The glaciation degradation amounted to 538.82 square kilometers in 1953–1973, 169.1 square kilometers in 1973–1985, 65.49 square kilometers in 1996–2010, 175.4 square kilometers in 2010–2020. A slight increase of 52.08 square kilometers was noted from 1985 to 1996. The biggest decrease was fixed among small glaciers (Kasatkin, Kupolovidnyy, Irkutskiy) — area losses of more than 78 %, and the least — among large glaciers (Leningradskiy, Kropotkin, Musketov) — the average loss of 21–24 %. The maximum average rate of area reduction was recorded from 1953 to 1973 at the amount of 0.78 % a year.
In the following period, a slight decrease in the rate of glacier degradation was noted (0.48 % a year) and from 1985 to 1996 there was an increase of glacier area at a rate of 0.17 % a year. The reduction in glaciation, which began between 1996 and 2010 at a rate of 0.17 %/year, sharply increased (almost 3.8 times) in the last studied period from 2010 to 2020 and reached an average value of 0.64 %/year. At the same time this value for Kasatkin glacier (the maximum among all glaciers) was 6.75 % a year. The decline of glaciers occurs against the background of a gradual increase in the average annual temperature (approximately 5 °C over the past 30 years). Since 1998 a stable increase in the average summer temperature (+ 2.8 °C in 2020) has been fixed. In addition the intensive degradation of the island’s glaciers may be connected with the fact that since 2010 a gradual increase in the sum of positive temperatures has been noted. With an average value of 118.5 °С for the entire study period, an abnormally high total of 429.4 °C was noted in 2020.

Artem E. Pshenichnikov
Candidate of Geography Sciences
Associate Professor of the Department of Cartography
and Geoinformation Systems School of Natural
Tyumen State University
6, Volodarskogo str., Tyumen, 625003, Russia
e-mail: a.e.pshenichnikov@utmn.ru
ORCID: 0000-0001-7423-0309
SPIN-код: 5659-5462
AuthorID: 417273

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