Home – Home – Jornals – Earth’s Cryosphere 2022 number 5

New experimental data have been obtained on the Workman-Reynolds freezing potential of water and the electric current from an external source through the ice melting front. A new model of the phenomenon is proposed, which takes into account the capture of protons and hydroxide ions by interstices of the ice lattice acting as charge traps. The model provides a semi-quantitative explanation of the observed features of the phenomenon.

The prerequisites and modeling of possible outburst floods in the valley of the Bodomdara River (Tajikistan) are considered using detailed field data. According to the route survey results, Lake Bodomdara Upper is a supraglacial lake, which assumes possibility of its outburst leading to a cascade outburst flood. The depression of Lake Bodomdara Lower is relatively stable, and its outburst is possible without cascade flooding at anomalously high temperatures, upon snowmelt combined with extreme rainfall. Two probable scenarios are considered: (I) the outburst of Lake Bodomdara Lower (its volume comprised 328 000 m³ according to the bathymetric survey of 2020) and (II) the cascade outburst flood of Lake Bodomdara Upper (700 000 m³). Digital elevation model (DEM) ALOS PALSAR (12.5 m) and DEM based on images from an unmanned aerial vehicle for the Bodmodara River alluvial fan were used for predicting flood consequences. The outburst flood hydrographs for scenarios I and II were obtained using the lake outburst model developed by Yu.B. Vinogradov and an empirical formula, respectively. The material increment was estimated in the transport-shift model of mudflow formation. The resulting hydrograph was applied for zoning the Bodomdara and Shahdara river valleys with a total length of 75 km based on the FLO-2D model. According to the modeling, the maximum water discharge at the top of the alluvial cone of the Bodomdara River will reach 143 m³/s under scenario I and 348 m³/s under scenario II.

Many elements of the natural environment are areal objects that change their position and shape at all scales of variability. For sea ice, such elements can be fast ice, drifting ice, polynyas, ice massifs, boundaries of multi-year ice. In other earth sciences, these are the boundaries of glaciers, permafrost, snow cover, forest zone, various isolines of meteorological and oceanological fields (isotherms, isobars, etc.). To analyze such objects, approximations in the form of a grid area (rasterization) or a system of sections are usually used. In this article, we suggest a direct analysis of these objects based on operations with vector polygons. An efficient algorithm for calculating the probability (frequency of occurrence) of an unlimited number of polygons has been developed and tested. A criterion for selecting one of the real edges of a polygon as an analogue of the isoline of probability of intersections of polygons is proposed. The developed method has been tested using data on the fast ice of the Kara Sea taken from the digital ice charts developed by the Arctic and Antarctic Research Institute for 1998-2020. As a result, the maps of fast ice probability for the cold season of each year and for a given time of the year for the entire considered period have been obtained. Based on these data, the operational characteristics of fast ice have been estimated, and a tendency for a decrease in the area of fast ice during the considered period has been revealed. For the beginning of May (period of the maximum development of fast ice), analogues from factual observations characterizing extreme, median, and quartile probability isolines of fast ice occurrence have been found.

The results of studies of the methane content in the active layer and upper permafrost horizon in the areas of the Marre-Sale station (western Yamal Peninsula) and the Pechora River mouth are presented. Data on the methane content in Quaternary permafrost and ground ice of different geneses and data on methane emission from the surface of typical tundra in Marre-Sale are analyzed. The highest methane content in sediments of both the active layer and the upper permafrost is characteristic of boggy floodplains and waterlogged depressions on the surface of the marine terrace. In well-drained landscapes, methane is virtually absent in sediments of the active layer. In the upper permafrost, its content 5-6 times higher than in the overlying active layer. A large amount of methane (on average, about 2 mL/kg) is contained in loamy clay marine sediments at the base of the Marre-Sale section, as well as in the massive ice. The distribution of methane in permafrost and ground ice is close to a lognormal distribution. Significant methane flux (up to 10.7 mg/(m² ·h ) has been determined for highly moistened surfaces occupying about 45-50 % of the area of a typical tundra.

Conditions of the origin, existence, and melting of the superimposed ice are considered for Bellingshausen Ice Dome on Fildes Peninsula of King George (Waterloo) Island near Antarctic Peninsula. Every year, accumulation of superimposed ice on the ice dome reaches about 15 cm. In years with positive mass balance on the ice dome, the thickness of superimposed ice increases. The maximum measured thickness of perennial superimposed ice on the ice dome is equal 145-150 cm reaching 300 cm in some places. Significance of the superimposed ice in the ice mass balance of Bellingshausen Ice Dome in different years during the observation period from 2007 to 2021 is estimated. It is argued that regime field observations are necessary for finding seasonal boundary of the superimposed ice as the altitude of the equilibrium line.

Doctor of Geographical Sciences, chief researcher of the Laboratory of General Geocryology of the Melnikov Permafrost Institute, Siberian Branch of the Russian Academy of Sciences, Aleksey Aleksandrovich Galanin passed away on September 8, 2022. A well-known specialist in geomorphology, evolutionary geography, and paleogeographic reconstruction of periglacial landscapes of the northeast of Russia in Pleistocene and Holocene, Aleksey Galanin will be remembered as a talented researcher with lively mind, enthusiasm, and passion for science, a warm-hearted and wonderful person.