Changes of high-latitude freshwater content (FWC) play an important role in shaping the variability of polar oceans. FWC is defined as depth-integrated departure of salinity from a reference salinity S_ref divided by this S_ref . A constant S_ref is often used for high-latitude FWC estimates. Here it is argued that for analyzing FWC spatiotemporal changes the use of local mean S_ref is a better choice. Analysis of 2007 FWC anomalies in the 25–75 m layer demonstrated, for example, that the choice of S_ref = 34.8 (which is often used in climate studies) leads to FWC spatial anomalies exaggerated, on average, by ~0.6 m, which is a substantial fraction of total spatial FWC changes. The problem is aggravated in areas where the difference between the local S_ref and S_ref = 34.8 is greater. Thus, it is concluded that using climatological mean salinities as S_ref provides superior estimates of spatiotemporal Arctic Ocean FWC changes.

Since 2006, a new generation of reinforced ice class Arc7 vessels has been operating on the Northern Sea Route. Safe and efficient sailing of this type of vessels in sea ice demands a detailed study of ice conditions. Accumulation and analysis of data on ice and hydrometeorological conditions for the entire Arctic in comparison with ice conditions along the route of vessels is an essential part of the development of optimal variants and optimal routes for ice navigation.
The main aim of the study was to generalize the conditions of ice navigation of Norilskiy Nickel vessels along the optimal navigational routes in the south-western part of the Kara Sea. Based on the reports on sailing obtained from vessels of the “Norilskiy Nickel” type for the 2006–2014 period, we calculated the probability of choosing the optimal route along the Murmansk – Dudinka passage: through the Kara Gate Strait (seaward, central or coastal route) or the north of Cape Zhelaniya. During the year, vessels move predominantly through the Kara Gate. However, for three month per year, from April to June, the most appropriate route lies to the north of the Zhelaniya Cape. In April – May it is, on average, every second navigation, and in June – more than 80 % of all navigation. The features of the ice regime determining the choice of the specific navigation route, are described. The speeds of vessels of the “Norilskiy Nickel” type along various navigation routes in drifting sea ice of the Kara Sea are calculated. The fastest speed in drifting ice was recorded in the winter navigations of 2007–2008 and 2011–2012, in the January-May of these years the average speed was 10.2 and 11.2, correspondingly. The minimum speed in these years, even during the months of maximum ice cover growth, was not less than 4.8 knots. In other years, the average speeds were in the range of 9.2–9.8 knots. During the whole period of study, ice conditions that were extremely difficult for navigation formed three times: at the end of May 2009, at the end of March 2010 and in the middle of March 2011, these are considered in more detail in the present article.

Given the significant changes in the climate on the planet as a whole, databases and archives of data on the main climate-forming characteristics of the atmosphere, collected over long periods of time in various regions of the globe and, in particular, in the polar regions, acquire a special role. Total solar radiation is one of the most important parameters affecting the energy balance of the Earth-atmosphere system. We have created a database (DB) of hourly and daily sums of total radiation (Q) at the Russian Antarctic stations, designed to study the radiation regime of the Antarctic, from the beginning of actinometric observations to 2019. The information presented in the database was collected at five Antarctic stations — Bellingshausen, Vostok Mirny, Novolazarevskaya and Progress. The database has undergone a state registration procedure and is registered under No. 2020621401.
The article gives a description of the structure of the DB and presents detailed information for each station. To provide an example of how database information can be used, characteristics of the total radiation in different parts of the Antarctic continent are obtained. Thus, it is found that the average monthly amounts of Q in the continental part of Antarctica on the high plateau (Vostok station) in conditions of minimal cloudiness and high transparency during the Antarctic summer are maximum and average 1240 MJ/m2. At the same time, at the tip of the Antarctic Peninsula (Bellingshausen station) during the same period, the average monthly amounts of Q due to the almost constantly present cloud cover do not exceed 570 MJ/m². In the coastal areas at the three remaining stations, the average monthly amounts of total radiation range from 908 MJ/m² (Progress) to 950 MJ/m² (Mirny). Estimates of variability characteristics of daily, monthly, and annual sums of total radiation at all the five stations for the entire observation period up to 2019 were also obtained. The absence of statistically significant long-term trends in the annual and monthly sums of total radiation at all the stations under consideration was noted. The results of their analysis indicate that there are no significant changes in the inflow of total solar radiation to the Antarctic surface over more than sixty years of actinometric observations.

A study of the content and composition of polycyclic aromatic hydrocarbons (PAHs) in the solid fraction of the snowpack is carried out on the territory of the Yamal-Nenetz Autonomous region, the north of Western Siberia. The total content of ten three-six nucleus PAHs was determined in the 51 samples collected at various distances from oil and gas producers and roads, near settlements, and in remote Arctic areas. The total PAH content varies from the lowest 0.3 ng/mg on the Bely Island, increasing to ~ 5 ng/mg in areas of new gas fields, and up to high 15 ng/mg in cities. Characteristic features of PAHs composition under the influence of gas flares emissions in central areas of high technogenic load are identified; they are a total content of up to 144 ng/mg and enrichment with low- molecular weight PAHs. In remote Arctic regions, high-molecular weight 5–6 nucleus PAHs dominate. Profiles of individual PAHs near gas flares, roads and residential sector facilities have been determined. The percentage contribution of the sum of 3, 4 and 5, 6-nucleus PAHs to the total PAH content indicates the gas flaring impact. Ratios of fluorantene to pyrene and benzene(b)fluorantene to benzene(ghi)perylene indicate changes in the snow PAHs composition with a decrease in the gas flaring contribution. The data obtained for the assessment of gas flaring emission impact on the PAHs composition in the snowpack are relevant to polar areas where new fields are being developed.

The paper investigates the current regime of turbulent heat exchange with the atmosphere over the Barents and Kara Seas, as well as its spatial, seasonal and temporal variability (1979–2018). It is shown that over the past decades, the areas of the location of the centers of maximum energy exchange between the sea surface and the atmosphere have not changed significantly in comparison with the middle and second half of the XX century. It was revealed that the greatest seasonal and synoptic variability of heat fluxes is typical of the central and western parts of the Barents Sea. It was found that both indicators of variability in the cold season are 2–5 and more times higher than in the warm season, and the spatial heterogeneity of the indicators of variability in winter is about twice as large as in summer. Quantitative estimates have shown that, within the Barents Sea, the spatial variability of fluxes in winter may be 5–10 times or more higher than the summer values. Above the Kara Sea, the greatest heterogeneity in the fluxes field is typical of the autumn and early winter seasons. It has been found that the annual sums of heat fluxes from the surface of the Barents Sea exceed the values for the Kara Sea, on average, 3–4 and 5–6 times, for sensible and latent heat fluxes, respectively, and in some years may differ tens of times. For the period under study, a single trend of the integral fluxes over the water area and their annual magnitude is not expressed, although there are multi-year decadal fluctuations. It is shown that, despite the significant difference in the thermal regime of the Barents and Kara seas and the lower atmosphere above them, the interannual changes in the total turbulent flows are quite well synchronized, which indicates the commonality of large-scale hydrometeorological processes in these seas, which affect the energy exchange between the seas and the atmosphere.

The study aims to identify formation factors of water inflow to the Antarctic lakes of the Larsemann Hills oasis (East Antarctica). The objects of study are 11 lakes of the oasis. The analysis was performed based on the expeditionary data of the Russian Antarctic Expedition (RAE): 63rd season (23 December 2017 – 3 February 2018), 64th season (12 January 2019 – 27 February 2019), 65th season (2 November 2019 – 24 March 2020). Data of lakes water level observations, aerial photography of the unmanned aerial vehicle (UAV) and route surveys are given, the results of identifying the boundaries of the lakes catchments are presented. The factors that determine the formation of water inflow to the lakes in this region were identified based on the analysis of the materials. The most significant are the meteorological conditions, the presence of perennial snowfields and glacial areas in the catchments, and the presence of lakes that can cause outburst flood. The seasonally thawed layer also has an impact on the formation of the inflow to the lakes. The vegetation cover is not so important for inflow formation in this region due to the physical and geographical conditions. As for anthropogenic activity, it mainly affects the environmental situation of the catchments and water quality, while the anthropogenic influence on the formation of water inflow to the lakes in the oasis is limited to the territories of polar stations. The factors identified should be taken into account in the further study of hydrological processes, the creation of models that describe them, and the organization of field observations.