Given the active development of the Arctic with an extremely rare network of observations, there is a high demand for reliable hydrometeorological forecasts of the ice, marine and meteorological conditions in this region. For this purpose, a system has been implemented for hydrometeorological forecasting of atmospheric, ocean and sea ice circulation parameters for the White Sea region. The polar version of the WRF model was used for predicting atmospheric circulation, the ROMS model was used for predicting ocean (sea) circulation, and the parameters of the sea ice state were calculated using the CICE model. Early results of calculating hydrometeorological parameters have been obtained and an assessment of the quality of calculations has been carried out, which helped to identify the advantages and disadvantages of the system used. For the atmospheric calculations, the errors are at or below the published estimates from similar papers. The fields of sea surface temperature, surface salinity, and ocean level are in good agreement with the GOFS 3.1 analysis data and are at the level of other authors' quality assessments. Inaccuracies have been identified in the reproduction of the above characteristics at the ice /open water boundary. For the sea surface temperature, errors at the ice /open water boundary reached 0.4 °C, for salinity 0.4 ‰, for current velocity up to 0.18 m/s, and a level of 0.2 m. A comparative analysis was carried out for two schemes of parameterization of ice thermodynamics in the CICE — BL99 and Mushy models. It is shown that when both schemes are used, a systematic overestimation of the total volume of sea ice is observed. However, compared to the Mushy scheme, the simpler BL99 scheme had fewer errors.

The paper presents experimental studies of anomalous propagation of medium radio waves. Radio echo signals with unusually long delay times of 310–324 ms were recorded at the transmitter point of the sounding signal. The experimental results can be explained by the guiding effect, when a radio wave penetrates into a waveguide channel oriented along the Earth's magnetic field line. In this case, the radio wave propagates to the magnetic conjugated point in the southern hemisphere and returns to the transmission point traveling a distance of 93,000 km. The echo signals were recorded with the use of AARI-developed transmitting and receiving measuring equipment that has a minimum radiation power of 1 kW, while in the previous LDE observation experiments the radiation power was 5 and 17 kW. For the first time, echo signals that radiated from the Earth's surface were recorded not at a single fixed frequency, but in a frequency band of 400 kHz, from 2.100 to 2.400 kHz. The noise environment at frequencies below 2.100 kHz did not allow us to determine the lower boundary of the channel. Analysis of the background geophysical conditions was performed. It was shown that the long delayed echo (LDE) signals were observed under disturbed magnetic conditions (the planetary magnetic index Kp = 4+) in evening hours. The echo signal frequencies exceeded the critical frequencies of the ionosphere at the transmitter point and were less than the critical frequencies at the magnetically conjugate point. A distinctive feature seen from the CADI ionograms was the presence of the F3S layer, which is the main signature of the development of a subauroral polarization stream (SPS) near the station's zenith. Swarm satellite observations revealed that the Gorkovskaya observatory was located at the bottom of the main ionospheric trough (MIT), near its equatorial boundary. The projection of the plasmapause was also located at the MIT bottom, between its polar boundary and Gorkovskaya. Plausible mechanisms for the creation of a waveguide along the magnetic field line were considered. The guiding effect may find practical significance in the development of means and methods for ground-based monitoring of space weather parameters, as well as radar sounding of the near-Earth space.

The recent warming of the Arctic causes degradation of permafrost, release of greenhouse gases due to the decomposition of previously frozen organic matter, increase in the area and diversity of vegetation, and decrease of in the bearing capacity of permafrost soils. In this regard, the evolution of the seasonally thawed soil layer is of particular interest. The paper presents the results of comprehensive studies of energy exchange processes in the atmospheric surface layer and the upper layer of permafrost, carried out in 2016–2020 at the Research Station “Ice Base Mys Baranova” (Bolshevik Island, Severnaya Zemlya Archipelago), supplemented by the results of model calculations of seasonally thawed depth (STD) dynamics. The study examines the role of surface snow albedo decreases due to short-term intrusions of warm air masses, leading to the intensification of snow melting and soil surface heating due to increase in absorbed incoming solar radiation, is analyzed. A version of the Leibenson model, validated by data of observations, is used for assessing the role of landscape factors and meteorological conditions in the dynamics of STD. Despite the simplified formulation of the problem and the approximate assignment of heat and mass transfer of soil properties in the area under study, the model results could be considered satisfactory, and proposed approach can be used for assessing the state of STD.

Studies of the present-day Arctic climate are becoming increasingly relevant and in high demand in the light of the observed global warming and the expansion of long-term programs for the development of the Arctic regions. A quantitative assessment of changes and variability in surface air temperature (SAT) is presented for the climate norm period of 1991–2020, based on data from 31 meteorological stations (MSs), which reflect the diversity of climatic conditions in the area studied. Average monthly SAT values were taken as indicators of changes in the thermal regime, and the standard deviations (SD) of average monthly SAT were used as indicators of the thermal regime variability. The annual course of SAT (one maximum and one minimum) mainly reflects the radiation factor. The annual course of SD (in the northern part of the area — one maximum and one minimum, in the southern part — two maxima and two minima) reflects the patterns of the atmospheric and ocean circulation and the type of the underlying surface. The assessment of the changes and variability in the thermal regime of the surface atmosphere was based on a comprehensive analysis of the annual cycle of indicators on the SAT-SD plane using closed SAT-SD curves characterizing annual and seasonal cycles. 31 SAT- SD curves were classified, and the corresponding regions of the Barents and Kara Seas were identified. A typical SAT-SD curve was obtained for each region. The boundaries of natural climatic seasons (NCS) were determined based on a comparative analysis of the seasonal cycle of SAT-SD indicators and the absolute SAT-SD values characteristic of different seasons within each region. Zoning and determining the duration of the NCS refine the general understanding of the climate of the Western sector of the Arctic.

The primary sources of nutrients in the Arctic are river runoff and remineralization processes. However, the local characteristics of coastal ecosystem functioning are strongly influenced by the supply of nutrients from glacial meltwater, particularly in regions where glacier-fed streams interact with the bedrock. In this study, we tested the hypothesis that rocks which form the bedrock of glacial streams, such as sandstones, siltstones, shales and carbonates, can serve as significant sources of nutrient elements (notably nitrogen and silicon) for coastal ecosystems. Laboratory experiments involving the exposure of representative rock samples to distilled water for up to 30 days demonstrated a measurable increase in nutrient concentrations. The observed leaching rates for nitrate nitrogen and dissolved silicon reached up to 7.9 micromoles per square meter per day and 30.7 micromoles per square meter per day, respectively, in the most reactive samples (these were sandstone from Stepovogo bay and siltstone from Blagopolychia bay). The results indicate that the release of nutrient elements from glacial bedrock, particularly during periods of enhanced meltwater runoff, can contribute significantly to the balance of nutrients and primary productivity of Arctic coastal ecosystems.

The water balance method has not been widely used in the study of Antarctic oasis lakes, therefore the structure of their water balance is not determined to date. The paper is aimed at the quantitative estimation of water balance elements and identifying the features of the water balance structure for lakes with different types of level regime, using as an exampe 9 lakes of the Larsemann Hills. The raw data include field work materials of the Russian Antarctic Expedition, meteorological data from the Progress station and satellite images Landsat 8-9. The water balance calculations were carried out for December-January 2019/20 and 2021/22. The study quantitatively confirmed the predominance of meltwater inflow in the feeding of open and closed lakes, while in the incoming balance part of flowage lakes from 40 % to 70 % is occupied by channel inflow. Channel outflow predominates (more than 95 %) in the outcoming balance part of most open and flowage lakes, whereas for closed lakes evaporation from the water surface predominates. It has been established that changes in the water balance structure are caused by those in the flowage types of water bodies, which also lead to a change in the types/subtypes of the water level regime. Based on the identified quantitative relationships of water balance elements, seasonally ice-covered lakes were classified into two categories: evaporating-inflowing and runoff-inflowing lakes (according to the classification by B.B. Bogoslovskiy). The identified features of the water balance structure can be useful for the analysis of observed water level data or for hydrological calculations.

The study is aimed at identifying the most general patterns of changes in the average global sea level in the Late Quaternary (the last 800 thousand years). The factual material used included recently published most detailed and reliable stacked series of the Global Sea Level (GSL) and Global Mean Surface Temperature (GMST) for the given time interval. On the scale of a 100-ka cycle, a simple linear relationship is observed between the two parameters (lower temperature – lower sea level), but upon closer examination, unusual features are revealed: 1) sea level maxima and minima are delayed relative to temperature maxima and minima by 4.7 ± 1.1 and 7.8 ± 2.1 thousand years, respectively; 2) ocean low stands are observed at approximately the same GMST anomalies (–4.7 ± 0.2 °C relative to the pre-industrial), while there is no correlation with the sea level value itself. The situation with the ocean high stands is similar. According to our hypothesis, the apparent delay in the sea level is explained by the fact that the maximum (minimum) ocean levels are not related to temperature per se, but to the accumulated sum of positive (negative) temperature anomalies over the previous warm (cold) period. In other words, the sea level series is a function of the integral-difference curve (IDC) of temperature. To illustrate this hypothesis, we have constructed a temperature IDC for the time interval between 460 and 360 thousand years ago, which satisfactorily explains the main trends in sea level change during marine isotope stages 12 and 11.

The modern development of Earth remote sensing methods has enabled scientists to make the huge breakthrough in the field of sea ice information support of maritime operations in the arctic and other freezing seas.
Nowadays ship navigation teams regularly receive near the real time satellite data, ice maps and ice forecasts. Nevertheless, the situations when satellite information has either insufficient resolution or is not transmitted aboard on time are not rare. In the case of ship stuck in the heavy ice conditions or when choosing an ice station for scientific work it is necessary to perform the ice reconnaissance directly from the ship. Such tasks can be solved with the use of a helicopter, nevertheless it is safe and cheaper to use unmanned aerial vehicles (UAV).
The article provides material that combines longstanding experience of conducting an operational sea-ice information support for maritime operations, of aerial ice reconnaissance, special ship-based observations of the sea ice key characteristics as well as experience of operating various unmanned aerial systems in high-latitude conditions by the scientists of the Arctic and Antarctic Research Institute. This paper aims to structure the flight and operational characteristics of the unmanned vehicle (UAV), as a platform useable for operational sea-ice information support of ship navigation in ice. The main objective of the article is to clearly outline the specifics of application and technical requirements for unmanned systems, both currently used and newly developed, which in turn will allow a wide range of professionals to avoid errors at the stage of planning the use of UAV systems, as well as during aircraft development and design. To solve this task the article highlights key criteria of medium range ice reconnaissance from the icebreaker, ice reconnaissance techniques, maximum parameters of meteorological conditions for UAV usage, the ways of UAV returns on the ship, and necessary equipment details.

The article examines the history of opening first automatic meteorological stations (AMS) for the Arctic in the Soviet Union in the 1930s, which measured meteorological parameters and transmitted them by radio. The idea of opening the stations belongs to the aerologist P.A. Molchanov. He invented the world’s first radiosonde for studying the atmosphere and in 1927 patented its coceptual scheme. In 1928, he proposed using a similar method of transmitting weather data over a distance by radio in the design of a ground-based AMS. Prototypes of the Molchanov AMS system were manufactured and tested as part of the work of the 2nd International Polar Year in the Pamirs and the Tikhaya Bay polar station (Franz Josef Land) in 1933–1934 and were the first in the world. This demonstrated the fundamental possibility of such devices operating in high- altitude and Arctic conditions, despite major testing problems. In 1935–1937, an improved AMS prototype was put into trial operation at the Tiksi polar station. P.A. Molchanov also worked on the creation of a drifting AMS, although these plans could not be realized. To date it has been a practically unknown fact that automatic weather stations were developed in the design department of the Leningrad State Factory of Meteorological Instruments “Metpribor”. Several samples of stationary and parachute AMS were made there in 1934–1936. The documents preserved in the collection of the Arctic and Antarctic Research Institute (AARI) and the state archives of St. Petersburg, periodicals, research literature and a number of other sources made it possible to reconstruct the history of developing and improving the design of the first AMS in our country. Much of the information is provided for the first time.