Abstract: The research has been made on the basis of an array of ice data for the maximums and minimums seasonal distribution of sea ice in the Northern Hemisphere. The probability range for the appearance of positive differences after the negative ones in March is greater than in September, and conversely. During the periods of minimum (March) and maximum (September) interannual changes, after positive differences with an increase in the number of differences in the group, the values of subsequent changes increase. There is an increase in the probability of a one sign occurrence interannual difference with an increase in the group of another sign previous differences. For the probability of zero differences (absence of variability), there is an increase in both the probability of zero values and the number of previous zero differences. The results indicate the presence of a stabilization mechanism in the stochastic interannual variability of the sea ice area, which is confirmed by an increase in the probability of the appearance of a one sign and the number of previous differences of another sign in the group. An increase in the probability of zero values with an increase in the number of previous zero differences confirms the presence of geographical areas in which there are no interannual changes in the area of sea ice.

Keywords: sea ice dynamics, solar radiation, ocean temperature, interannual variability, stochastic processes, Markov chains, area of sea ice, Northern Hemisphere, sea ice, meridional insolation gradient

Abstract: The object of the study is the isotope composition of three aufeis (icing) in the Viluy River basin. Two of the three tested icing were located in the wide valleys of the streams-tributaries of the Viluy River, one on the flat bottom of the thermosuffusion sinkholes. The areas of studied icings did not exceed 30 sq. m., their thickness ranges from 45 to 100 cm. Stratification is recorded in the icings. The co-isotope diagram δ2H-δ18O shows that icing ice was formed from spring water and generally is isotopically “lighter” compared to the water of Kysyl-Yurekh stream and Viluy River. The isotope composition of the icing ice varies in a very narrow range: a) for icing 1 δ18O values vary from –19.3 to –20.9‰, δ2H values vary from –156.5 to –162.9‰; b) for icing 2 δ18O values vary from –19.7 to –22.4‰, δ2H values vary from –153.2 to –173.1‰; c) for icing 3 δ18O values vary from –19.8 to –22.7‰, δ2H values vary from –162.9 to –181.3‰. The similarity of the isotope profiles of icing 2 on Viluy and icing IB93-5 on Baylot Island and isotope profiles of icing 3 on Viluy and icing F192-6 on Baylot Island was noted, however, the scale of isotopic variations for icings on Baylot Island are 5-6 times greater than that of Viluy icings.

Keywords: cryolithozone, Yakutia, Viluy, deuterium excess, deuterium, oxygen isotopes, river water, snow, permafrost, aufeis

Abstract: The subject of this research is the correlation analysis of changes in the area of sea ice in separate regions of the Arctic, and levels of internal regional correlations between multiyear monthly changes in the area of sea ice of different seas and the entire Arctic Ocean. The author also examines peculiarities in the annual amplitude course of interannual variability of monthly indices of the area of sea ice for separate districts of the Arctic, interregional links in the annual course of this amplitude of interannual variability, and determination of correlation between the annual indices of the area of sea ice with annual insolation contrast for various Arctic regions. The research method is the correlation data analysis on the area of distribution of sea ice in different districts of the Arctic and insolation contrast. The author builds an algorithm of the value forecast in the changes of sea ice area. Based on the analysis of internal correlations between multiyear and annual changes in the sea ice area in the Arctic regions, and connection with the insolation and insolation contrast, an algorithm is proposed for the value forecast of changes in the sea ice area in separate districts of the Arctic and Northern Hemisphere overall. For long-term forecast of annual values of the changes in sea ice area, the promising districts are Baffin Bay, Kara Sea, Barents Sea, Greenland Sea and Northern Hemisphere as a whole.

Keywords: regional correlation, Arctic seas, prediction algorithm, correlation analysis, insolation contrast, Earth insolation, area change, sea ice, satellite observations, regression model

Abstract: On the basis of theoretical calculations of insolation and Earth remote sensing data on the dynamics of the sea ice area in the Arctic Ocean, a close relationship between long-term changes in the sea ice area and annual insolation contrast in the Northern hemisphere was determined. The change in insolation contrast was generalized (in terms of the source and sink of heat) reflects the change in the meridional insolation gradient that regulates the meridional heat transfer in the ocean - atmosphere system. The regression model was used to make an estimated forecast of changes in the area of sea ice in the Arctic Ocean. According to our estimates, the reduction of the average annual sea ice extent in the Arctic Ocean in 2050 will be 18.3% relative to 2018. The Maximum area (March) will be reduced by 10.1%, and the Minimum area (September) by 60.3%. The decrease in the area of sea ice is associated with an increase in the meridional gradient of insolation and meridional heat transfer resulting from a decrease in the inclination of the Earth's rotation axis in the present epoch.

Keywords: meridional heat transfer, insolation contrast, meridional insolation gradient, sea ice, satellite observations, Earth insolation, regression model, estimated forecast, sun radiation, Arctic

Abstract: The aim of this study is to estimate the Amderma station (the Kara Sea) ice-free period using sea ice concentration satellite datasets in comparison to observation data. The work follows the research performed for the Western Coast of the Yamal (Marresalya) being the part of the Arctic coastal dynamics study. The OSISAF, JAXA and NSIDC (resolution 25 km, 1 day, 1979-2018) sea ice concentration datasets were used to characterize the water area adjacent to the station within the 30-50 km radius. The threshold (15%-concentration) and the author's "sliding window" methods were used to detect open water start and end dates. According to the satellite data, the ice-free period in the 30-50-kilometer water area along the Amderma coast is shifted by 2-3 weeks closer to December if compared to observations. At Amderma station (in the contrast to Marresalya), there are no significant trends in ice-free period start dates. On the adjacent water area, the destruction of the ice cover occurs earlier by 3-6 weeks if compared to the 1980’s, and the end date by 3-6 weeks later. The duration of the open water period over 40 years has increased by 32-36 days at the station and by 52-120 days (40-100%) in the adjacent water area.

Keywords: climate change, Amderma, Kara Sea, Arctic coasts, satellite datasets, sea ice concentration, open water period, ice-free period, open water period duration, coastal dynamics

Abstract: The article contains the results of field investigations of cryospheric objects – land-based glaciers and permafrost rocks in the area of the Lavrenty Bay, Eastern Chukotka. Glaciers of the Laurentian group were described in the mid-1970s by Rudolf Sedov, later they were studied with the help of space imagery by one of the authors. Since glaciers are of small size, and satellite images can give errors in this case, it was necessary to check in situ their condition. Field studies have made it possible to ascertain the severe degradation of small glaciers of the Chukchi Highlands. Also field studies of the permafrost seasonal thawing, carried out by the authors in the season of 2017, revealed that the difference in thickness of the seasonally thawed layer in the study area at the end of August was, in comparison with the previous year, -0.5 .. + 4.3 cm, depending on local natural conditions. 

Keywords: Eastern Chukotka, permafrost, climate change, rock glacier, active layer, glacier, Chukchi Highland, Chukotka, glaciology, geocryology

Abstract: The paper contains the results of the hydrological generalization of the features of river ice regime of the Arctic zone of Western Siberia. The rivers under study (Nadym, Pur, Taz, the lower Ob and others) flow in swamped lowland in the area of permafrost, which defines the peculiarities of their hydrological conditions. The author studies the ice regime of navigation and ice crossing on these rivers. Special attention is given to the characteristics of the level regime in the period of ice phenomena, which helps define the danger of ice-related floods. The research is based on the data of 40 stage gauges from the start of measurements to 2014. The author demonstrates the patterns of special distribution of the main characteristics of the ice regime, determined by the dependence of average values on the geographic latitude of the studied areas. The author considers regional peculiarities of the conditions of ice level growth during the ice formation period and defines the floodable inhabited areas. 

Keywords: the Arctic, ice-related flood, ice thickness, ice break, freezing, river ice conditions, Ob, Nadym, Pur, Taz