The problem the frozen soil mapping of the steppe zone

The results of the frozen soil mapping for the Southern Part of Western Siberia are presented. We analyzed the satellite radiometer's data of MIRAS (frequency of 1.4 GHz), AMSR and AMSR 2 (frequency of 6.9 GHz and 10.7 GHz) for 2010-2016 years. The identification of the frozen soils' area on this territory is difficult even with the implementation of a joint analysis data of these radiometers. The reasons for this are the following. Often at late autumn season the soil moisture at this region has low value. Sometimes wet snow falls on the unfrozen soil surface. In this case determining the start of the freezing of the soil under the snow is impossible. As a sign of the beginning of soil freezing process the data on the thermodynamic temperature of the soil surface may be appropriate. Rarely, the moist soil without snow on surface quickly freezes to the depth greater than the sensing depth of radiometer. In this case the frozen soil area may be easily identified.