The climate changes observed over the past few decades are most clearly manifested in the Arctic Ocean. Sea surface temperature (SST) is one of the most reliable indicators of climate change. In this paper we analyze the changes of winter SST for the western, northeastern and southeastern regions of the Barents Sea and examine the relationship of the emerging STS trends with the influence of various external factors. The working data set is represented by average monthly SST values taken from the ERA-5 reanalysis for the period 1949–2023 with a spatial resolution of 0.25×0.25° and average water temperature values on the Kola Meridian section in the 0–50 m layer. Additionally, the Arctic Oscillation (AO), Arctic Dipole (AD) and Atlantic Multidecadal Oscillation (AMO) indices were used as external factors that may affect SST variability. The time series analyzed was divided into three periods: 1949–1969, 1970–1990, 1991–2023, where the variability of the analyzed parameters was different. Thus, in the first period the trend in SST changes was negative, for the second period it was slightly negative or neutral, and for the third period it was positive. It is shown that SST in all the regions of the Barents Sea has undergone significant changes, which were most noticeable in the “warm” period of 1991–2023, when the rate of SST increasing was up to 10·10-2 °C/year in areas under the warm Atlantic water influence. The analysis of SST variability in the Barents Sea shows that the positive anomalies observed in the recent years are most likely associated with the changes in the atmospheric circulation. The Wavelet coherence analysis showed the closest agreement between the changes in the sea surface temperature and the AD index in the winter season, and with the AMO index.

Among the physical parameters of the freezing seas ice cover, ice thickness is of key importance, and its measurement is one of the most important tasks. The increased interest in the state of the sea ice cover as an indicator of global climatic changes, as well as the growth of comprehensive development of the Arctic shelf has caused intensive development of technical and methodological bases for ice observations. Despite the great variety of approaches to ice thickness estimation, all of them are not without weaknesses. Thus, most contact methods imply direct human presence, which significantly complicates the procedure, taking into account, among other factors, the rough weather conditions of the Arctic. Remote methods depend on weather conditions and cannot always provide high spatial resolution. In this connection, it is promising to use satellite observations coupled with the results of autonomous “ground” measurements, which can be seismoacoustic data containing information on the characteristics of elastic waves propagating in the ice-covered sea, is promising. The purpose of this work is to experimentally test a new passive method for monitoring ice cover parameters along long profiles based on the analysis of natural seismoacoustic fields. The article analyzes the data of a full-scale seismoacoustic experiment with a multichannel group of geophones placed on the floating ice of Alexandra Island in the Franz Josef Land archipelago within the framework of a complex expedition of the Russian Geographical Society. The demonstrates that it is in principle possible to use flexural-gravity waves propagating in the floating ice to estimate its characteristics, both in the active mode and by analyzing the ambient noise, is demonstrated. The results of ice parameter reconstruction obtained in a nondestructive manner using seismoacoustic waves and averaged over long profiles are compared with the data of direct contact measurements. This can be further used for monitoring seasonal and multiyear variability of sea ice thickness of freezing seas, including shelf zones.

The annual water temperature in the major water masses of the Barents Sea (BS) has significantly increased since the early 2000s. Advective heat transport from the neighboring water areas and heat exchange through the sea surface are the major factors, which shape the hydrological conditions in the BS. The paper estimates the contributions of heat exchange at the sea-atmosphere boundary and advective heat transport to changes in the average water temperature of the BS for the entire sea area. The average annual heat balance of the BS is calculated using atmospheric and oceanic reanalysis data. The change in the average temperature of the BS water is estimated taking into account the heat consumption for ice melting. The average surface heat balance from 1993 to 2018 was negative throughout the entire sea area: –70…–100 W/m2 in the south and –10…–20 W/m2 in the north. The advective heat supply was calculated for 9 straits with neighboring water areas. The determining source of advective heat is the influx of Atlantic waters from the Norwegian Sea between Cape Nordkapp and Bear Island. An average of 40.8 TW of advective heat is supplied through this margin. The calculations showed the predominance of annual heat influx due to advection over heat loss from the sea surface. This excess heat influx resulted in an estimated increase in the water temperature of the BS from 1993 to 2018 at a rate of 0.28 °C per year (taking into account the heat consumption for ice melting). In conclusion, it can be argued that the analysis has validated the hypothesis proposed in the article about compensation of heat losses from the surface of the BS by advective heat flow. The hypothesis is quantitatively confirmed by calculations on a simple box model (with an accuracy of up to an order of magnitude) based on atmospheric and oceanic reanalysis data. The ERA5 and GLORYS12V1 reanalysis data reliably describe the basic patterns of observed variability of ocean, sea ice and atmospheric parameters in the Barents Sea.

The development of the Northern Sea Route and the beginning of year-round transit shipping require not only the production of new icebreakers and ice-class vessels, but also the development of a specialized hydrometeorological support system for ice shipping. For the analysis of satellite data and the development and validation of ice forecasts, actual field data on the ice cover is required. This data can only be obtained from shipboard observations; however, scientific expeditions are rarely organized during the winter. In order to obtain new data over the area of intensive shipping, two expeditions were organized on board of nuclear icebreakers in the southwestern Kara Sea (“LED-SMP” expeditions) in 2023 and 2024. Specialized hydrometeorological maintenance of ice shipping in the southwestern Kara Sea together with the research expeditions “LED-SMP” carried out in the same place and time on board the nuclear icebreakers revealed the influence of the technogenic factor on the sea ice structure and dynamics was revealed. In winter and spring, two main routes are used for navigation in the southwestern Kara Sea: through the Kara Gate Strait and north of Cape Zhelaniya. In April 2024, a unique situation occurred when, due to the difficult ice conditions east of the Kara Gate Strait, the entire ship traffic was directed north of Cape Zhelaniya. In preparing a long-term ice forecast, it was noted that after the redirection the natural development of ice processes changed. At the beginning of the winter period 2024,

Since 2017 we have carried out aerosol sampling at the research station “Ice Base Baranova Cape” (Novaya Zemlya Archipelago) with the purpose of studying the variations in aerosol physicochemical characteristics: the concentrations of ions, microelements, organic and elemental carbon (ОС and ЕС), as well as the isotopic composition of carbon δ13C in the aerosol. The average summed concentrations of ions throughout the period of measurements were 1,99 μg/m3, the concentrations of elements were 51,1 ng/m3; and those of ОС and ЕС were 398 and 25 ng/m3, respectively; the isotopic composition of carbon δ13C was–27.6 ‰. The main contribution (73 %) to the ion composition of atmospheric aerosol is due to “marine” ions Na+ and Cl-, and the contribution to the elemental composition is due to terrogenic Fe and Al (71 %). The large enrichment coefficients (with respect to Na+ in sea water) were manifested for ions SO 2-, K+, and Ca2+. Aerosol enrichment by these ions is the largest in the warm period. In the aerosol elemental composition, we identified large enrichment coefficients (with respect to Al in the Earth’s crust) in elements Se, Sn, Sb, Mo, As, Zn, Cu, Cr, Pb, and Cd, indicating their technogenic origin. The nearest sources of aerosol enrichment by technogenic elements are plants for mining and processing mineral resources in the Taymyr Autonomous Okrug. The statistical generalization of the multiyear data allowed us to calculate for the first time the annual average behavior of the chemical composition of aerosol in the study region. With respect to the seasonal variations, the ions and elements can be divided into three groups: 1) with winter maximum (Na+, Cl-, Mg2+, Br-; Se, Cd, V, Co, As); 2) with summer (PO 3-, NH +, CH SO3-, F-) or autumn (Al, Ti, Li, Sr, Fe, Zn, Ba, Ni) maximum; 3) with poorly defined or indefinite variations in other ions (NO -, K+, SO 2-, Ca2+) and elements (Cu, Pb, Mo, W, Sn, Cr, Sb, Mn). As most of the other characteristics, the annual behaviors of the ОС and ЕС concentrations are characterized by the general maximum in the winter-spring period. In addition, a second maximum is manifested in the ОС content in the summer-autumn period. The average monthly carbon isotopic composition in the aerosol varies in the range from –28.3 ‰ (February) to –27.3 ‰ (May).

For many years, the dominant opinion in the literature has been that the stratospheric polar vortex is weaker in the easterly phase of the QBO than in the westerly phase, which is known as the Holton–Tan effect. While for the Northern Hemisphere vortex this is true during winter, for the Southern Hemisphere vortex the dependence on the QBO is observed only in spring. This feature is usually explained by the greater intensity of the Southern Hemisphere vortex compared to the Northern Hemisphere vortex, and the QBO can modulate its strength only during the vortex breaking season in October-November. Usually, the vortex response to the QBO is determined based on the equatorial wind direction at a certain vertical level, and the conclusions depend strongly on the level at which the QBO phase is determined. However, it has long been shown that using the equatorial wind sign at one or even a combination of several levels is not quite correct because it does not take into account the time of descent of the QBO wind relative to the seasons of the year, and it is not known at what altitudes the QBO wind has the strongest influence on the extratropical stratosphere. Due to the variable period of the QBO cycles, the phase relationship between the seasonal cycle and the QBO cycle is constantly changing, resulting in many variants of the vertical structure of the wind QBO during the Antarctic winter vortex and ozone hole. However, the seasonal regularities of QBO used in this work lead to a strictly limited number of possible variants of coincidence of the phases of the QBO cycles with the seasons of the year, which allows us to reveal typical features of interannual variations of the polar vortex and ozone hole in the Antarctic that are due to the QBO. The analysis of observational data indicates unexpected peculiarities of the QBO modulation of the stratospheric polar vortex in the Antarctic. The QBO effect in the vortex intensity is observed not only in spring during the weakening phase of the winter vortex, but also during the vortex maximum in June–August. At the same time, changes in the wind speed of the vortex during its maximum in winter are opposite to those in the spring during the ozone hole period. If the winter vortex is more intense (weak), then during the ozone hole period the vortex is weaker (more intense) than the average level.

The paper examines the relationship between the PC index, characterizing the solar wind energy input into the magnetosphere, and the AL index, characterizing the magnetic substorm intensity for the expansion phase of isolated substorms recorded in 1998–2017. Magnetic disturbances in the course of the expansion phase are produced by the DP11 current system with a powerful westward electrojet disposed in the midnight auroral zone. It is generally accepted that this electrojet is generated by the “substorm current wedge” system of fieldaligned currents (SCW FAC) providing closure of the magnetotail plasma sheet currents through the auroral ionosphere. As this takes place, magnetic disturbances in the course of the substorm growth phase are produced by the DP12 current system with westward and eastward electrojets located, correspondingly, in the morning and evening sectors of the auroral zone, with the electrojets generated by the R1/R2 FAC system operating in the inner (closed) magnetosphere. The intensity of R1 currents is determined by the “coupling function” EKL, which represents the optimal combination of all geoeffective solar wind parameters affecting the magnetosphere. The DP2 magnetic disturbances generated by the R1 FAC system in polar caps forms the basis for estimating the PC index, which strongly follows the EKL field changes and correlates well with the development of magnetic substorms. Analyses performed in AARI revealed the principally distinctive character of the relationships between the PC index and AL index in the course of the substorm growth (DP12 disturbances) and explosive (DP11 disturbances) phases. The DP12 disturbances, generated by FAC systems in the closed magnetosphere, are developed in strong relation to the PC index. The DP11 disturbances, generated by the SCW FAC system, related to the magnetotail plasma sheet, show quite irregular character of relationship between the PC and AL values: the sudden jumps of the substorm intensity (ALpeaks) might occur, time and again, at any value of the PC index and with quite different delay times relative to sudden substorm onset. It means that the processes in the tail plasma sheet, leading to the formation of a “substorm current wedge” are determined by the state of the magnetotail plasma sheet itself. The solar wind influence (evaluated by the PC index) affects but does not control the processes in the magnetotail, unlike those in the inner magnetosphere. It should be noted in this connection that the intensity of magnetic DP12 and DP11 disturbances, observed in the course of the substorm growth and explosive phases, is estimated by a single AL index, in spite of the different origin of these disturbances (R1/R2 and SCW FAC systems). It is necessary to employ two separate indices characterizing DP12 and DP11 disturbances in order to allow for the effects of the solar wind on the processes in the inner magnetosphere and in the magnetotail.

Т. In recent decades, the distribution and activation of thermodenudation, which leads to the formation of specific landforms — thermocirques (also referred to as retrogressive thaw slumps, RTS), have been intensively studied. In different regions of the cryolithozone and at different time intervals, both activation and stabilization of thermocirques are observed. As a rule, studies focus on the climatic controls of the phenomena observed, the environmental controls are discussed less often. This study presents an analysis of the dynamics of thermocirques in relation to the relief features in a specific key area of Central Yamal. To achieve this aim, the spatial distribution of thermocirques at different geomorphological levels is considered based on multi-temporal remote sensing data. Satellite images obtained in 2009, 2018, and 2023, as well as a global digital elevation model (ArcticDEM), were used. We outlined five geomorphic levels and determined their parameters: area, altitude, steepness, and the aspect of the slopes. Thermocirques were identified in the images and their parameters were measured. The dynamics of the thermocirques were analyzed by their number, area, length, width, slope aspect and angle for the periods 2009–2018 and 2018–2023, and for 14 years in total, separately for each geomorphic level. It was found that thermocirques predominate on the slopes of the III alluvial-marine plain, 5–12° steep. In 14 years, the total area of thermocirques increased by 296 %, and their number — by 61 %. A larger increase in the total area and number of thermocirques occurred during the period 2009–2018 in response to climate extremes in 2012 and 2016. Thermocirques that face west cover a higher total area, partly due to the predominance of such slopes over the area of the key site. In all the years of observation, the average areas and lengths of thermocirques are maximum on south-facing slopes. Some of the results are close to those obtained in other regions of Russia and in North America. In many of the areas studied, the increase in the total area of thermocirques exceeded the increase in their number, which means that the expansion of the existing forms prevails over the inception of the new ones. The discrepancies observed in different studies in the results of assessing the effect of relief on thermocirques are due to both the regional features and differences in satellite imagery and methods of its processing.