According to the meteorological station Barentsburg the average positive temperature of air on West Spitsbergen for the period of 1985–2011 years grows by 0,02 °C/year, and for the period of 2002–2011 it is reduced on 0,03 °C/year. The average negative temperature of air for these periods grows with intensity 0.09 °C/year and 0.20 °C/year, accordingly. Tendency of the growth of the snow cover maximal thickness is kept. During 2007–2009 the maximal thickness of snow cover reached 2 m. As a result of it deterioration of soil conditions is freezing. The temperature of soil on the depth of 1 mreaches –6 °С for maximal snow thickness of 0.5 mand it reaches –1 °С for snow thickness of 2 m. During the summer period the growth of soil temperature is interfered by the moss cover. The depth of thawed soil is reduced more than 80% for a moss thickness 10 cm. In winter, the moss is not an essential obstacle for soil freezing and cooling. The moss heat conductivity coefficient in winter corresponds to the snow heat conductivity coefficient for density 400 kg/m 3 . Results of mathematical modelling and calculations are showed that at real meteorological parameters and absence of the moss cover talik can formed.

The paper presents results of analysis of diurnal and potentially possible efficiency of water freezing aimed at construction of artificial infiltration (firn-ice) masses on the Russia’s territory. A method of jet ice-formation (winter sprinkling) developed in Institute of Geography of the Russian Academy of Sciences is used for freezing of the artificial firn-ice masses. The method applies far-reaching (long-distance) sprinkler installations for spraying of water and formation of thick (more than 7 m for a day) masses of artificial firn. In winter the sprinkler allows freezing of both the monolithic ice and artificial firn. A practical implementation of this method is licensed and realized for construction of ice passages, bridges, and winter automobile roads. Testing of the method demonstrated that the artificial firn can be used for desalination and purification of polluted salt waters with high efficiency. That is stipulated by both, the high productivity of the method (about 1500 tons of artificial firn for a day at the air temperature of −20°С, and low mineralization of the firn relative to initial salt water. Winter sprinkling is carried out when mean daily air temperature drops below –5 ∞С. Estimating of productivity of the artificial firn and monolithic ice under present-day climatic conditions was made over the Russia’s territory. Analysis of the climate conditions for periods 2001–2010 and 1961–2000 have shown that reduction of the firn productivity changed from 5-10% in Siberia up to 20–40% in central and southern regions of the European Russia. At the present time, a potentially possible volume of the artificial firn freezing being produced in cold seasons changes from 500 thousand tons in northern areas of Yakutia down to 10 thousand in center of European Russia. Productivity of the monolithic ice freezing by a method of thin-layer water pouring is twice lower in central areas of Yakutia than on the Arctic seashores that is explained by differences in wind speeds. Potentially possible monolithic ice productivity made by means of thin-layer water pouring changes from 56 m of ice thickness in Northern Siberia down to 10 m in center of European Russia. The Northern Yakutia and the River Ob’ mouth are two areas of maximal productivity of this method.

Spatial and temporal variability of snow thermal resistance in some areas of Krasnoyarsk region and Yakutia has been studied. Soil freezing depth has been correlated with snow cover depth and its thermal resistance. Mathematical modeling has been applied to assess the influence of snow cover and soil parameters on depth of frost penetration. The critical thickness of snow cover that controls the development of seasonally frozen layer disconnected from underlying permafrost was found. Capabilities and efficiency of controlling the thermal resistance of snow cover required to reduce the adverse effects of climate warming on permafrost degradation have been discussed.

Space and time variations in the thermal resistance of snow have been studied in several areas of the Krasnoyarsk region. The depth of snow has been correlated with its thermal resistance and with frost depth depending on the properties of snow and soils. The dependence of thermal resistance on snow stratigraphy, with different snow grain sizes, ice crusts, and depth hoar has been illustrated by examples from Spitsbergen and Moscow area. Neglect of snow stratigraphy can lead to 1.5 times underestimation of thermal resistance.

Depth and rate of the soil freezing are stronly determined by dynamics of snow accumulation during the first half of a cold season. Dynamics of snow accumulation over two periods (1966–2000 and 2001–2010) was analyzed using data of snow surveys performed on the European part of Russia and in basins of rivers Ob and Yenisei (Siberia). The ratio a of snow cover thickness measured for the first half of the cold season (untill January 1st) to the maximal thickness for the whole period is taken as a characteristic of the snow accumulation dynamics. Maps of the ratio a on the above areas had been constructed. During the last period (2001–2010) values of this ratio increased by 10–20% in regions to the East of the Lena river, and they decreased by 15–40% in the European part of Russia and in basins of rivers Ob and Yenisei. Model calculations did show that differences in the soil freezing depths under different conditions of the snow cover growth sometimes exceeded 50%. Interannual variability of the snow thermal resistance and the snow cover influence.

На Западном Шпицбергене, по данным метеостанции Баренцбург, средняя положительная температура воз- духа в период 1985-2011 гг. (с июня по сентябрь) увеличивалась на 0,02 °С/год, а с 2002 по 2011 г. она снижа- ется на 0,03 °С/год. Средняя отрицательная температура воздуха (с октября по май) за указанные периоды росла с интенсивностью 0,09 и 0,20 °С/год соответственно. Cохраняется тенденция роста максимальной тол- щины снежного покрова. В 2007-2009 гг. она достигала 2 м, что ухудшило условия промерзания грунта. При максимальной толщине снежного покрова 0,5 м температура грунта на глубине 1 м достигает −6 °С, а при толщине 2 м составляет −1 °С. Летом нагреванию грунта препятствует моховой покров. При его толщине в 10 см глубина протаивания грунта снижается более чем на 80%. Зимой моховой покров существенно не влияет на промерзание и охлаждение грунта, так как коэффициент теплопроводности мха в зимний период соответствует коэффициенту теплопроводности снега плотностью более 400 кг/м3. Результаты математиче- ского моделирования и численных экспериментов показали, что при существующих метеорологических условиях и отсутствии мохового покрова возможно образование талика.