No 3 (2023)
Articles
Features of the mechanism of aerosol fractionation in solid hydrometeors
Abstract
The object of the study is the dispersed fractions of an aerosol substance in the snow cover. At the sampling sites located in the middle taiga zone within the Mezen-Vychegoda Plain on a high terrace in the Sysola river valley, 3 km west of the city of Syktyvkar, fresh snow and surface frost were sampled. The analysis of the ratios in the surface hoarfrost of subdispersed fractions of the aerosol substance was carried out in conjunction with the granulometric analysis of freshly fallen snow. Studies using the method of dynamic light scattering of the granulometric composition of an aerosol substance in freshly fallen snow and surface hoarfrost formed between snowfalls showed that a bimodal distribution of particles is recorded in all snow samples. At the same time, the distribution of submicron aerosol particles in frost samples is already characterized by the presence of three modes. Also, with an increase in the duration of the period between snowfalls in hoarfrost samples, a redistribution of particles between fine and medium fractions is observed in the direction of a significant increase in particles in the fine fraction, but the volume concentration of particles of the large fraction changes slightly. It is assumed that the identified circumstance is associated with the action of capillary forces and the adhesion of dry precipitation during the crystal formation of hoarfrost (it is proposed to call this phenomenon "frosty condensation"). A similar effect was also observed in the West Siberian southern taiga and the coastal tundra of the Lower Pechora region.
Arctic and Antarctica. 2023;(3):1-15
1-15
Calculation of the coefficient of thermal conductivity of snow cover
Abstract
The aim of the work is to obtain generalized simple formulas for calculating the coefficient of thermal conductivity of snow cover when calculating its thermal resistance. To achieve the goal, a comparison was made of the parabolic formula of N.I. Osokin, obtained on the basis of generalization and correlation analysis of existing dependencies for calculating the coefficient of thermal conductivity having fractional coefficients, with its simplified version with integer coefficients. Based on the linearization of the base Simple linear formulas for determining the coefficient of thermal conductivity depending on the density of snow for two characteristic density ranges (200-300) and (300-400) kg/m3 were also obtained. The percentage errors in the calculations of the coefficient of thermal conductivity of snow, which are possible with the simplification of the coefficients and linearization of the basic parabolic dependence of the coefficient of thermal conductivity on the density of the snow cover, are determined. It is established that the errors arising from the linearization of the basic function do not exceed 5%, which is quite acceptable in engineering calculations. The discrepancy between the results of calculations according to the basic and simplified formula (with coefficients rounded to integer values of the first order) does not exceed 1.5% in the entire considered range of changes in snow density. The results of numerical calculations are presented in the form of graphs that allow you to visually assess the impact of simplifying the calculation formula and its linearization on the accuracy of determining the coefficient of thermal conductivity of snow cover.
Arctic and Antarctica. 2023;(3):16-23
16-23
Cryogeochemical features of Holocene and Late Pleistocene syngenetic ice wedges at the mouth of the Seyakha (Zelenaya) River, East Yamal Peninsula
Abstract
The purpose of the paper is to establish the range of variability of mineralization and ionic composition of water-soluble salts in ice wedges of different ages near the Seyakha village (Eastern Yamal Peninsula) in outcrops of the river floodplain, Holocene peat bog and yedoma, as well as to establish the contribution of atmospheric nutrition of ice wedge and structure-forming ice. In the ice wedge of the yedoma the total mineralization is very variable from 17 to 309 mg/l, which indicates the participation of Ob Bay waters in addition to atmospheric waters. Sometimes there is a noticeable presence of sea salts in the sediments of the floodplain at the mouth of the river, associated with the influx of Ob Bay waters during surge surges of the bay level in the mouth of the river. It has been revealed a noticeable change of the mineralization of structure-forming ice in the Holocene peat, its regular gradual decrease from bottom to top is from 576 to 18 mg/l. This indicates that the reason of the lacustrine-marsh basin (or rather, several small basins) formation was the thawing of large masses of highly mineralized segregated and pore ice contained in the upper part of the lagoon-marine terrace. As the peat bog accumulated, the role of atmospheric precipitation increased, and in the final phase of ice formation in the upper part of the peat, atmospheric precipitation completely dominated.
Arctic and Antarctica. 2023;(3):24-51
24-51
Possibility using carbon-to-nitrogen ratio as a criterion for palsa and lithalsa distinguishing
Abstract
The palsa and lithalsa are reliable indicators of the presence of permafrost, especially on the its southern border. The subject of the study is the consideration of the C/N ratio in the peat of the palsa and the litter and humus horizon of the lithalsa as a criterion for the separation of the palsa and lithalsa. The palsa near the Yeletskaya village in the Bolshezemelskaya tundra and the lithalsa in the Southern Transbaikalia near the Preobrazhenka village and in the valley of the Sentsa in the Eastern Sayan are considered. The history of the study of lithalsa and palsa in Russia at the beginning of the twentieth century is considered also. It was found that the nitrogen content in the surface layers of the lithalsa (0.45-1.73% in the valley of the Sentsa River and 0.47-2.01% near the Arachley Lake) is approximately in the same range as in the surface horizons of the palsa, regardless of the permafrost region. The results of the carbon and nitrogen content determining, as well as their ratios in the peat cover of the palsa are summarized. In contrast to lithalsa, the carbon content in the peat horizons of the palsa and flat-hummock peatlands is many times higher than the values obtained for both surface and buried organic horizons of the lithalsa. The value of C/N less than 13 has not been recorded for the peat cover of palsa, this indicator for lithalsa never exceeds 10-12.
Arctic and Antarctica. 2023;(3):52-72
52-72
Features of radiothermal study of ice in the microwave range
Abstract
The subject of the study is ice formations, which are formed as a result of the release of groundwater to the surface of ice sheets or soil. These formations cause significant damage in human economic activity. The work investigated natural ice located on fresh ice cover, as well as artificial ice formations on the ground. The glaciers located in the Transbaikal region near the city of Chita were investigated. The power of thermal radiation of these objects in the microwave range was determined at wavelengths of 2.3 cm and 0.88 cm. The power of thermal radiation in the microwave range was determined using radiometric receivers at wavelengths of 0.88 cm and 2.3 cm mounted on a car or on a fixed support. Cores of ice removed from the ice were studied to determine the layer-by-layer distribution of ice mineralization. A model of a plane-layered non-isothermal medium was used to calculate the thermal radiation of ice. The possibility of registering ice formations by radiothermal radiation of these objects in the microwave range is shown. If there is a layer of water on the ice, the radio brightness temperature will be significantly lower than the object on the surface of which there is no water mass. By the value of the radio brightness temperature in the microwave range for several ranges, as a result of which it is possible to indirectly estimate the thickness of ice formations. At the same time, it is necessary to take into account the variations in the radiofrequency temperature of the medium depending on its thickness due to the interference of radiothermal radiation of a plane-layered medium.
Arctic and Antarctica. 2023;(3):73-85
73-85