Seasonal thawing of soils in Beringia region in changing climatic conditionsтезисы доклада

Дата последнего поиска статьи во внешних источниках: 17 октября 2017 г.

Работа с тезисами доклада

[1] Seasonal thawing of soils in beringia region in changing climatic conditions / A. Maslakov, V. Ruzanov, D. Fyodorov-Davydov et al. // International Conference Earth's Cryosphere: Past, Present and Future (June 4-8, 2017, Pushchino, Russia). Program and conference materials. — 2017. — P. 44–45. Active layer develops in warm period of the year in cryolithozone and occupies an intermediate position between the atmosphere and permafrost. Active layer thickness (ALT) is sensitive to changes in weather and climate. Although active layer formation mechanism and natural factors affecting its spatial distribution are well studied in regional scale, high local variability of ALT brings uncertainty to modelled results and often forms multidirectional trends in interannual variations of ALT. This study presents the results of long-term observations of the active layer dynamics in various parts of Beringia palaeo-region. The data are field measurements, conducted in framework of Circumpolar Active Layer Monitoring (CALM) program and study materials of Dionisiya field permafrost station (Anadyr area, Chukotka). The sites, considered in this study, have mid- to long-term series of observations (16 to 28 years) for active layer thickness and provided with meteorological data. The key sites of the study are: 1) Kolyma lowland, having 5 CALM sites, situated both in zonal (tundra and northern taiga) and intrazonal (floodplain) landscapres; 2) Anadyr lowland (Dionisiya field permafrost station) with 2 CALM sites, reflecting tundra foothills and river lowland conditions; 3) Eastern Chukotka coastal plains (sedge tundra); 4) NW Alaska, representing high-latitude polygonal tundra (Barrow) and shrub tundra (Seward peninsula). The analysis of interannual fluctuations of seasonal soil thawing depth and summer (June-September) air temperatures revealed common patterns and trends: the most of considered monitoring sites demonstrates increasing of active layer thickness, which was observed in 1980-1990, following increasing summer air temperature. This period was followed by relative stabilization in 2000-2010 and continuation of active layer thickening over the last several years. Several CALM sites in Kolyma lowland and in Eastern Chukotka demonstrates continuous ALT increasing during 2000-2010, even despite of summer temperatures stabilization. Obtained data shows ambiguity of cryosphere response to climate changes and requires necessity of further studies of interaction between active layer and natural conditions.

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