Abstract: Transport links and provision of hard-to-reach settlements and mining enterprises play an important role in the economic development of the Arctic regions. In winter, winter roads are used as transport arteries; their mode of operation depends on the characteristics of the ice. Winter roads are used in Russia, Canada, USA, Finland, and China. Due to climate warming, the timing of the formation of ice cover on rivers is shifting to later times, and in the spring the ice is destroyed earlier. This could affect the delivery of vital supplies to remote regions. According to recent forecasts, it is assumed that heavy vehicles will not be able to use winter roads by the end of the 21st century. The purpose of the study is to analyze changes in the characteristics of ice cover on the rivers of the Northeast of Russia. To do this, a series of data was collected for the period 1940–2018 on the thickness of the ice cover at 80 hydrological stations located in the basins of the Yana, Indigirka, Kolyma rivers, rivers of the Chukotka Peninsula and the Sea of Okhotsk basin. The catchment areas range from 18.3 to 635,000 km2, and the duration of the continuous series ranges from 2 to 67 years. Three statistical nonparametric tests (Mann-Kendall, Pettitt and Theil-Sen) were used for evaluation. The following characteristics were considered: the maximum ice thickness and the date of its formation, the dates when the ice thickness reached 60 and 90 cm. During the period under review, the maximum ice thickness decreased by an average of 40 cm, while the date of reaching the maximum values remained almost unchanged. The period for the formation of river ice with a thickness of 60 and 90 cm, necessary for the passage of cars and trucks, respectively, has shifted by almost a month. The start date of freeze-up occurs on average 3–4 days later, and the end date of freeze-up occurs 5–8 days earlier. On average, the duration of freeze-up decreased by 5–15 days. The results obtained must be taken into account when drawing up the work schedule for winter roads. This is especially important for regions where communication between populated areas and mining enterprises is possible only through river arteries.

Keywords: ice reduction, cryosphere, Arctic regions, ice phenomena, aufeis, climate change, ice cover period, winter road, the North-East of Russia, river ice thickness

Abstract: This paper describes the results of field measurements of methane and carbon dioxide fluxes from natural and anthropogenic-modified ecosystems located on the Norilsk industrial district. Previously, such studies have not been conducted in the area. The study points are located in different landscape regions determined by various conditions of permafrost formation. Most of the study area is located within the zone of predominantly continuous permafrost distribution. Six landscape regions were identified. Methane and carbon dioxide fluxes were measured at selected key sites typical for each region. When selecting the study points, the variety of conditions affecting methane and carbon dioxide emissions was considered. First, these include soil type (mineral or peat) and local moisture conditions. Methane and carbon dioxide fluxes were measured by dart static chamber method. Measurements of greenhouse gas concentrations in the chamber were carried out by a portable gas analyzer Li-7810 (Li-COR, USA). The results obtained show significant variability in greenhouse gas emissions for different ecosystem types. Methane uptake by soils is recorded on mineral soils and dry parts of bog ecosystems. Positive methane emissions are typical for watered areas of bog ecosystems and lakes with maximum values in the hollows. Methane fluxes range from slightly negative in dry bog areas with a median of -0.026 mgCH4/m2/h to emissions of 0.802 mgCH4/m2/h as the median for watered areas of bog ecosystems. Carbon dioxide fluxes are inversely correlated with the ecosystem moisture content and have a range from 51.6 mgCO2/m2/h (median for lakes) to 576 mgCO2/m2/h (median for mineral soils). A medium strength correlation was found between surface air temperature and intensity of methane uptake by mineral soils was found. Probability density distributions of methane and carbon dioxide fluxes have different forms.

Keywords: lakes, freshwater ecosystems, specific fluxes, chamber method, carbon balance, landscapes, permafrost, bogs, carbon dioxide, methane

Abstract: The subject of this article is exmination of the influence of the Arctic air flow on the climatic conditions of the winter period in the center of the European territory of Russia (Moscow). In recent years, the question of the relationship between regional climatic conditions and such global circulation patterns as the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AK) has become increasingly important. Based on the data of long-term observations of temperature and precipitation, the relationship with the AK and NAO was considered. For the winter months of the period 2014-2018, the back trajectories of the movement of air masses were computed for each date of precipitation to identify the sources of precipitation. The amount of winter precipitation that forms the snow cover of Moscow has no connection with either the North Atlantic Oscillation or the Arctic Oscillation. The Moscow region is located at the intersection of the zones of influence of positive and negative phases of both cyclonic patterns (AK and NAO), which determine the weather in the Northern Hemisphere. For the winter months, a correlation between the surface air temperature and NAO (r = 0.72) and AK (r = 0.66) was established. Winter precipitation in the center of the European territory of Russiais mainly associated with the unloading of Atlantic air masses. Arctic air masses relatively rarely invade Moscow region and bring little precipitation (their contribution does not exceed 12% of the total winter precipitation).

Keywords: North Atlantic Oscillation, Arctic oscillation, source of air masses, Moscow, precipitation, air temperature, snow accumulation period, winter precipitation, European territory of Russia, climate change

Abstract: The subject of this research is the current state of wind regime in the Arctic and variability in response to the global warming. The performed analysis concerns both, the average value of wind speed and the extremely high that exceed the specified threshold value in the present-day conditions and in the late XXI century. The authors examines the spatiotemporal variability of the value of wind speed of different frequency in the Arctic territory for the climate system models that participated in the World Climate Research Program CMIP5. Particular attention is given to the regional peculiarities of climate forecast of wind speed over the seas of the Russian Arctic. The results are obtained from the data of reanalysis ERA-Interim and climate system models of the CMIP5 project for the current (Historical experiment) and forecast (experiment RCP8.5) climate. The main result of this research became the quantitative estimates of climatic forecast of the average and extreme wind speed in the Arctic by 2100 in terms of implementation of RCP8.5 scenario, which implies the most rapid rise of temperature throughout the XXI century. It is acknowledged that with the ongoing warming over the major part of the Arctic, the growth trend of not only the average, but also the extreme values of wind speed is typical for most models of the CMIP5 project. The decrease is noted over the greater part of the north of Eurasia, Greenland, the North Atlantic, the Norwegian Sea, while the rest of the Arctic is experiencing an increase in average and extreme wind speeds. The drop in temperature is recorded over the most of Eurasia, Greenland, North Atlantic and Norwegian Sea, while over the rest of the Arctic shows the increase in average and extreme wind speeds.

Keywords: sea ice, oceanatmosphere interaction, extremes, climate modelling, Arctic, climate change, wind speed, greenhouse effect, global warming, climate risks

Abstract: The author studies the change of climate resources of the Arctic in the context of global warming, forecast in the 21st century. The authors pay special attention to the values of climate resources, calculated on the base of temperature and precipitation values. The article studies daily points of extremum of surface air temperature, yearly amounts of air temperatures in different ranges and the longevity of periods with such temperatures, fuel performance index, amount and type of precipitations at different air temperatures, and the number of days with such precipitations. Climate resources are calculated on the base of a climate forecast of a group of climate models of the CMIP5 project for the RCP8.5. scenario. To estimate climate resources, the authors use daily model data about air temperature and precipitation total for the period of 1950-2100. in latitudinal zone of 60-90 degrees of north latitude. The authors of the present study are the first to acquire the results of a complex forecast of climate resources of the Arctic. The study shows that, in the context of global warming, the spatial heterogeneity of the forecast anomalies of climate resources is well-defined. The most vivid changes of hydrothermal climate resources by the end of the 21st century are expected above the Northern Atlantic, the seas of Western Europe, the Barents and the Chukchi seas. The least significant changes are expected above Greenland. 

Keywords: precipitation, temperature, global warming, climate models, climate forecast, the Arctic, climate resources, regional analysis, indexes, daily points of extremum

Abstract: The Novaya Zemlya bora is the strong abrupt wind, appearing on the western shoulders of the Novaya Zemlya mountain. Such winds reckon in downwind storms, appearing upon the wind flowing over mountains. They are characterized by the increase of wind speed, air temperature jumps and the lapse of pressure on the downwind side. The character of atmospheric disturbances on the downwind side is determined by the landscape and the parameters of the incident flotation. Therefore, the authors give special attention to the structure of the incident flotation and hydrodynamic criteria of the partial blocking of the flow with mountains. Based on the observation data and the MERRA reanalysis, the authors analyze 12 episodes of the Novaya Zemlya bora. They define the specific temperature and wind structure of the incident flotation -  the presence of the raised inversion level, the low-tropospheric streamflow at the altitudes, close to the mountain height, the wind reaction to the height. The authors reveal the decrease of the partial blocking of the flow by the mountains in the moments of the bora maximum development. The authors demonstrate that the wind speed during bora is controlled, primarily, by the mesoscale pressure gradient, which can appear in the result of gravity waves distribution over the mountain (wave resistance). The authors show that the Novaya Zemlya bora is very similar to Novorossiysk bora and other winds of this type.  

Keywords: supercritical flow, wind regime of the Arctic, flow blocking by mountains, downwind storms, Novorossiysk bora, the Novaya Zemlya bora, problem of flow over the mountain, orographic wind, Novaya Zemlya, extreme wind speed

Abstract: The palaeoreconstructions of the mean January temperatures based on the distribution of δ values (oxygen isotope composition) in the Late Pleistocene ice wedges in yedoma dated by radiocarbon are yielded. Verification of the equation linking current data of δ values in modern ice wedges with mean January temperatures has been done. In yedoma of different regions of the Russian Arctic formed 30-12 ka BP made the analysis reliability of radiocarbon ages. It is enabled to set on the time scale the isotopic events with high temporal resolution - with step 2-4 ka. New maps of the mean January palaeotemperatures for the time intervals 30-28, 24-22, 20-18, 16-12 ka BP are created for the Russian Arctic.

Keywords: cryochrone, palaeoreconstructions, Russian Arctic, Pleistocene, mean January temperature, oxygen isotopes, yedoma, ice wedge, radiocarbon, permafrost