LONG-TERM MONITORING OF THE ACTIVE LAYER THICKNESS IN TYPICAL TUNDRAS OF THE WESTERN YAMAL
A.A. Vasiliev, G.E. Oblogov, R.S. Shirokov
Earth Cryosphere Institute, Tyumen Scientific Centre, Siberian Branch of the Russian Academy of Sciences, Tyumen, Russia
Keywords: climate change, seasonal thawing depth, monitoring, dominant landscapes, surface subsidence, moss cover, Marre-Sale
Abstract
Data on the interannual dynamics of the seasonal thawing depth in the dominant landscapes of typical tundra at the Marre-Sale geocryological station (western coast of the Yamal Peninsula) are presented. It is shown that drained landscapes have the maximum response to changes in climatic conditions, while wet and boggy landscapes are characterized by the reduced rates of increase in the active layer depth. The slow increase in the depth of seasonal thaw during the current climate warming is explained by the presence of an ice-rich horizon in the upper part of permafrost, thaw subsidence, and an increase in the height of the moss cover. The uneven growth of vegetation, primarily mosses, creates considerable contrasts in the spatial distribution of the active layer depth. For a regional assessment of the thawing depth, the use of its mean weighted value with due account for the share of each landscape in the entire landscape structure of the region is recommended.
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