A METHOD FOR EVALUATING THE THERMOPHYSICAL PROPERTIES OF ACTIVE LAYER SOIL UNDER NATURAL CONDITIONS
V.E. Ostroumov1, D.G. Fedorov-Davydov1, I.A. Komarov2, F.A. Shevchik2, A.M. Koloskov2, M.P. Volokitin3, V.V. Goncharov1, S.S. Bykhovets1, V.P. Shabaev1, A.L. Kholodov1,4, I.I. Eremin5, D.Y. Kropachev5, S.P. Davydov6, A.I. Davydova6
1Institute of Physicochemical and Biological Problems of Soil Science, RAS, Institutskaya str. 2, Pushchino, 142290, Russia
2Lomonosov Moscow State University, Faculty of Geology, Leninskie Gory 1, Moscow, 119991, Russia
3Institute of Fundamental Problems of Biology, RAS, Institutskaya str. 2, Pushchino, 142290, Russia
4University of Alaska Fairbanks, 2156 Koyukuk Drive, Fairbanks, Alaska, USA
5JSC SPA Etalon, Lermontov str. 175, Omsk, 644009, Russia
6Pacific Geographical Institute, FEB RAS, North-East Scientific Station, Chersky 18, Sakha (Yakutia), 678830, Russia
Keywords: permafrost, soils, active layer, thermophysical properties, heat flux, temperature regime, geocryological monitoring
Abstract
Under natural conditions, soils of the active layer are open systems of varying composition, structure, and properties. However, in engineering projects, the values of thermal properties measured in laboratory on isolated samples of constant composition are used to describe their thermal state. To take into account the variability of the thermal properties of active layer soils under the influence of external factors, we propose a method for assessing the equivalent indicators of their volumetric heat capacity and thermal conductivity using a combined analysis of dynamics of soil temperature and heat fluxes based on long-term monitoring data. Monitoring of the heat flux and soil temperature has been carried out at two sites, one of which characterizing the area of seasonally freezing soils, and the other - the area of seasonally thawing permafrost-affected soils. A procedure for processing monitoring data is proposed, which makes it possible to determine the time-averaged effective values of the equivalent heat capacity and thermal conductivity. The proposed technique allows one to trace fluctuations of the equivalent heat capacity and thermal conductivity in time series against the background of changes in external factors of heat transfer in the active layer under natural conditions.
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