Earlier, the authors established a close relationship between the temperature of water coming from the North Atlantic and the sea ice extent (SIE) in the Barents Sea, which accounts for up to 75 % of the inter-annual variability of the monthly SIE from January to June. In turn, temperature variations of the incoming Atlantic water are affected from anomalies of sea surface temperature (SST) in the low latitudes of the North Atlantic. These dependences served as the basis for the development of a forecast method. The empirical orthogonal functions decomposition of the SIE set from January to June for 1979–2014 was used. The main component of decomposition reflects 83 % of the inter-annual variability of SIE from January to June. Regression model of forecast is based on the relation of the main component with SST anomalies taking into account the delay. Comparison of prognostic and actual values of the climatic component for each of the 6 months showed the correctness of forecasts with a lead time of 27 to 32 months is 83 %, and for the prediction of the initial values of SIE 79 %. Appealing to the second predictor — SST anomalies in the Norwegian Sea allowed to improve the quality of the forecast of the observed values of SIE. At the same time, the forecast advance time was reduced to 9–14 months.

Sea level observations obtained in various expeditions since 1936, as well as those made at the polar station on Cape Kamenny (the Ob Bay) from 1952 to 1994 were subjected to treatment and harmonic analysis using the least squares method (AARI version).The aim of the work was to assess the quality of hourly and 6-hourly intervals series of sea level data and to bring these data to uniform rows for the subsequent study of tidal and surge waves. As a result of this analysis, 6-hourly interval observations of 1952–1961 were considered of low quality and not suitable for further consideration in the work. Bringing 6-hourly interval observations for 1977–1994 to uniform rows was carried out first with the control of the height basis and binding to the Baltic system of heights, and then with the help of the tide calibration method the final cast was made. In the area of tidal fluctuations of the level, erroneous information about the tide, obtained during the treatment of observations for 1936, which were placed in the tide tables for 1941, was revealed. New average estimates of harmonic constants for the summer period were proposed. The study of surges of level is based on uniform series, as well as residual ones (observations minus predictions). At the same time, the tide calculation (prediction) was made according to the program developed at AARI for the average monthly values of harmonic constants (12 sets of tides lists in the annual cycle) with the inclusion of long-period tides. Statistical quantitative characteristics of non-periodic level fluctuations were obtained for the total and residual series of observations. They are calculated on a unique hourly series for the years 1947–1948. And 6-hourly interval data for 1977–1994. For the estimation of surges, the level above 5 % of estimation was used, and the drifts were distinguished by the level below 95 % of estimation. Relationships are obtained between the duration and rate of growth of the level during surges, as well as the decline and rise of the level during drifts.

The melting of glaciers in the Arctic archipelagoes provides glacier runoff, which must be considered when assessing river flow. Glacial runoff, as a component of the total river flow, directly affects the thermal and ice conditions of the bays, the productivity and species composition of the marine biota. Also, this process is broadly related to the livelihoods of the Arctic villages. Furthermore, it acts as the important factor for the development of transport and tourism. Melted water of Svalbard glaciers is a significant contribution in total runoff of the local rivers. The issue of this study is to assess this contribution. Grønfjord Bay was selected for assessment because of the fact of regular measurements of water discharge in the river estuaries from June to October. Among 7 rivers flowing into the bay, 6 have glacial runoff. Despite the fact that only small mountain glaciers are common in this area, its melting largely determines the water regime of the rivers. The value of the glacier runoff in Grønfjord Bay was calculated based on an estimation of the glaciers melting by average summer air temperature in 2017 and 2018. Comparison of the amount of glacial and total flow was carried out on the rivers flowing into the Grønfjord Bay.The comparative analysis of the glacial and total river flows size along the 6 rivers of the Grønfjord Bay: Grøndalselva, Grønfjorddalselva, Bretjørna, Aldegonda, Brydebekken, Vasstakelva showed significant differences in the glacier runoff content depending on the area of glaciation in the catchment of rivers. The content of glacial runoff in the total freshwater discharge by rivers into the bay in 2017 and 2018 vary from 20 to 90 %. The largest glacier runoff is observed on the Bretjørna river — 90 %, the Grøndalselva, Brydebekken and Vasstakelva have the smallest glacier runoff — 20 %. The average total glacial runoff of the rivers varied from 41 to 53 % of the total discharge of the rivers of the gulf.

The knowledge of the spatial distribution of the snow accumulation rate and isotopic composition in different scales, from local to continental, over the Antarctic Ice Sheet is critically important for the interpretation of the paleoclimate data obtained from deep ice cores, for correct assessment of the ice sheet mass balance, etc. With this in mind, we have synthesized geodetic, glaciological and geochemical data collected in the vicinity of central Antarctic Vostok station in 1970–2017 in order to shed light on the processes governing the spatial distribution of snow isotopic composition and accumulation rate in the spatial scale from 100 to 1000 m. First, we have discovered that snow surface height and snow accumulation rate field are strongly affected by the influence of the logistic convoy route annually operating between Russian Antarctic stations Vostok and Progress. This influence is detectable up to 1 km leeward from the route. At the same time the isotopic composition of the upper 10 cm of the snow does not show any anomalies in the vicinity of the route. This is an unexpected result, because large anomalies of the ice sheet surface (e.g., megadunes) are known to affect the snow isotopic composition. Second, in the undisturbed part of the snow surface near Vostok station we have discovered quasi-periodic (with the wavelength of about 400 m) low-amplitude variations of the surface height that are covariant with the corresponding waves in snow accumulation and isotopic composition. We suggest that spatial variability of the snow isotopic composition is due to the different ratio of summer and winter precipitation deposited in different locations, as evident from a strong negative correlation between δD and dxs parameters. The results of this study may explain the nature of the low-frequency noise (with the time-scale from decades to centuries) observed in the climate records obtained from shallow and deep ice cores in central Antarctica.

The determination of the main physical properties of the fast ice around the research station “Ice base Cape of Baranov” was carried out from May 23 to August 7, 2014. At the beginning of the observations the ice was a system of three main layers reflecting the conditions of fast ice formation. The top 70 cm of the ice was formed under the conditions of dynamic variability. The ice formation to the level of 110 cm was more stable, and the lowerst layer below 110 cm grew without hummocking and thawing. In the second decade of June the ice accretion began on top due to recrystallization on snow and ice boundary. In the third decade of June the accretion process at the ice-snow interface was replaced by surface melting and destruction layer development. These changes are assumed to begin as maximum air temperatures keep above zero. By the second decade of July all the ice core had undergone serious internal changes. In the third decade of July the process of inter-crystalline-binding degradation affected the whole ice core.

From the end of the third decade of June the formation of plate-like crystals was registered at the lower ice border, as well as the accretion of new ice in the form of layesr of various thickness and density. The process had reached the maximum by mid July when new ice up to 30 cm thick was formed. In the third decade of July this ice begun to melt. New ice accretion is primarily due to the presence of a layer of desalinated water under the ice.

The ice cover of the Arctic Seas is an important component of the natural conditions. It is impossible the construction and safe exploitation of the hydrotechnical structures and lines of communications on the shelf, reasonable planning and conducting of cargo and transport operations, organization of environmental protection measures without taking into account an ice cover.

The information on morphometric and dynamic characteristics of ice formations, physical and mechanical ice properties, presence of icebergs and its bergy bits with various mortphometric and dynamic characteristics in the water area are necessary for an organization of successful activity on the shelf (design of hydrotechnical structures, planning of the work etc).

The present article is concerned with the issues of estimation of ice formations morphometric parameters. The different remote observations methods on ice floes and icebergs are considered in the article: aerial survey, radar survey, observations using ice radar and geodetic instruments, visual observations, sonar survey of ice cover.

The goal of the work is the description of peculiarities of various remote methods of observations. For each of the considered methods, the conditions of its application and peculiarities of data obtainment are considered; the list of morphometric parameters, that can be estimated, using results of corresponding observations is indicated.

The mentioned algorithms and formulas are actively used during ice surveying works at the present time. The knowledge of various methods peculiarities allows to plan the composition of research works depending on their goals and tasks, determine the terms of their performance.

The main merits and demerits of the considered methods of data obtainment and estimations of ice formations morphometrical parameters are phrased in the conclusion.

Evolution of permafrost under thermokarst lakes is an actual question in the light of such problems of cryolythic zone research as greenhouse gas emission, permafrost degradation and cryovolcanism. Recently drained thermokarst lake provide an opportunity to study under-lake permafrost state with ground geophysical methods. This lake located on Kurungnakh island (composed of Yedoma ice complex deposits) in the Lena delta was studied with electrical resistivity tomography. Local low-resistivity anomaly in the central part of the lake was found during previous geophysical research. Main goal of this work is detection of residual thermal effect from a frozen under-lake talik in an electric field. Satellite images of different years show that the drainage has taken place about 30 years ago. The area of the lake was covered in 2016 by high-resolution aerial imagery (5 cm/pixel), then digital elevation model was built using photogrammetry. These data were used for geomorphological description of the alas (depression in permafrost after lake drainage). The alas depth reaches 8 m, its size is about 300 × 500 m. It was formed probably on the last stage of Holocene thermokarst activity and it is relatively shallow in comparison to other typical alases on the island. A number of baijarachs (as a result of polygonal ice wedges thawing) were observed on the alas bottom. A line of the steepest slope marks a coast line of the lake, which allows to estimate a volume of water, which was contained in it earlier. Electrical resistivity tomography was implemented on 8 parallel profiles of 235 m. Measurements were conducted with dipole-dipole array. Basing on 3-dimensional inversion results a 3-dimensional resistivity model of under-lake deposits up to 40 m deep was made. Relatively low resistivity area (16–25 kOhm·m in comparison to 50–100 kOhm·m) was registered at the depth of 15–35 m. It is probably linked to a temperature anomaly (–3...–5 °С in comparison with –8.5 °С average value of the region). Therefore the under lake talik was fully frozen but the rest of temperature anomaly is still observable. 3-dimensional finite-element modeling of talik propagation (500 years) and refreezing (30 years) was done in axisymmetric setting taking phase transition into account. Temperature anomaly up to 0 °С in its center at the depth of 35 m was obtained as a result of the modeling. It qualitatively confirms the interpretation of electrical resistivity tomography data on the residual temperature anomaly below the basin of the drained lake.

The article reports the results of the summer 2018 expedition to Cape Kamenny(of the Ob bay, Yamalo-Nenets Autonomous Region) and the nearby non-functioning oil product supply facility (OPSF).The aim of the study was to monitor the current environmental situation and assess the level of oil pollution of environmental objects on these territories. The field and laboratory studies revealed the need to treat and remediate the oil-polluted soils, water bodies and wetlands.

The field surveys of the territories showed the presence of visible oil polluted sites. The results of the laboratory tests revealed an excess of maximal permissible concentration (MPC) levels (1.3 – 6.2 MPC) for the water bodies located near the sources of oil pollution. The soil samples near the OPSF demonstrate a significant excess of oil products content (up to 1474 times). The soils sampled at Cape Kamenny are characterized by smaller content of oil products.

Since the non-functioning OPSF is situated on a territory that has always been poluted by oil, it seems necessary to develop a land remediation plan to rehabilitate the site and to prevent a further pollution of the adjacent territories due to the migration of the pollutants.

The oil pollution levels established for Cape Kamenny territory indicate a fairly high level of anthropogenic pressure in this area. Due to the low comparatively low soil stability in the area, it appears necessary to augment the measures for controlling the oil products leakage and spills at all the potentially hazardous objects.