PERMAFROST TEMPERATURE in THE UPPER KOLYMA HIGHLAND ACCORDING TO THE DATA OF THERMOMETRIC BOREHOLES 2021-2022
O.M. Makarieva1,2, D.A. Abramov3, A.A. Zemlianskova1,2, A.A. Ostashov2, N.V. Nesterova2
1North-Eastern State University, Magadan, Russia
2St. Petersburg State University, St. Petersburg, Russia
3Tyumen Research Centre, Siberian branch of the Russian Academy of Sciences, Earth Cryosphere Institute, Tyumen, Russia
Keywords: frozen ground, seasonal thawing/freezing layer, ground temperature regime, the Upper-Kolyma Highland, talik
Abstract
This study is aimed at a preliminary analysis of ground temperature data from ten thermometric boreholes drilled and equipped by the authors in the Upper Kolyma Highland (Magadan region) in 2021-2022. The boreholes of up to 15 m in depth are located in characteristic landscapes (rocky talus, mountainous tundra, larch woodland, river valleys) of the highland at heights from 618 to 1182 m asl. Continuous monitoring of ground temperatures with a time step of 4 h was carried out. Data on the mean annual rock temperatures, seasonal thawing/freezing depths, and the depths of zero annual amplitude were obtained. The mean annual ground temperature varied from -0.1 to -3.8 °C. The depth of seasonal thawing ranged from 0.9 to 2.6 m. The depth of zero annual amplitudes was 11.5 and 13 m in two boreholes. Two boreholes located in talik zones recorded freezing depths of 2.6 and 3.6 m. Ground temperature regimes within the same region differed significantly depending on landscape conditions: elevation, landform, composition of the rock, character of vegetation, and other factors. Based on the data obtained, it is planned to further develop the geocryological monitoring network in the Magadan region. For some of the boreholes, a full annual cycle of observations on ground and air temperatures, precipitation, and snow cover depth is available. As information on the state of permafrost in the territory under consideration is virtually absent, publication of the obtained data of relatively short-term observations is relevant and timely.
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