Академическое издательство «Гео»

Keywords: North-East of Asia, permafrost, taliks, cumulative positive temperatures, annual minimum of soil temperatures.



GEOGRAPHY AND NATURAL RESOURCES, 2019, № 2, p. 124-131

Annual temperature cycle in seasonally thawed and seasonally frozen soils of North-East Asia

A.V. Alfimov

Institute of Biological Problems of the North, Far Eastern branch, Russian Academy of Sciences,
685000, Magadan, ul. Portovaya, 18, Russia, arcalfimov@gmail.com

In the upper reaches of the Kolyma river and on the coast of the Sea of Okhotsk, 211 biotopes showed ecologically important temperature characteristics of seasonally thawed and seasonally frozen soils during warm and cold seasons. The highest (for the upper reaches of the Kolyma) cumulative positive temperatures (2000–2150 °C/day at a depth of 20 cm) can accumulate in the warmest soils of both types, whereas in the coldest seasonally frozen soils at the same depth this parameter (400–450 °C/day) is higher by a factor of 40–45 than in the coldest seasonally thawed soils. On the coast of the Sea of Okhotsk, formation of seasonally thawed and seasonally frozen soils is possible at any of the values of winter and summer temperatures. The limits of fluctuations of the minimum soils temperatures in hydrogenic taliks of both regions are determined: in the warmest soils at a depth of 20 cm they vary from –1 to –4 °С, or 4–6 °С higher than in the warmest permafrost biotopes; and in the coldest taliks (except in poplar-chosenia communities of floodplains) they are vary from –13 to –14 °C. Annual minima in the range between –6 to –8 °С and –23 to –24 °С can occur both in taliks and in permafrost biotopes, lower values in seasonally thawed soils only. Thus the annual minima of soil temperatures of most biotopes do not depend on the presence or absence of permafrost horizons, and only in a small part of hydrogenic taliks they are significantly higher than in the warmest permafrost biotopes.

Keywords: North-East of Asia, permafrost, taliks, cumulative positive temperatures, annual minimum of soil temperatures.

DOI: 10.21782/GiPR0206-1619-2019-2(124-131)

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