The Arctic polar vortex is often affected by wave activity during its life cycle. The planetary Rossby waves propagating from the troposphere to the stratosphere occasionally lead to the displacement or splitting of the polar vortex, accompanied by sudden stratospheric warming (SSW). In January 2009, one of the largest SSWs was observed in the Arctic. In this work, the dynamics of the polar vortex during the 2009 SSW is considered using a new method that allows one to estimate the vortex area, the wind speed at the vortex edge, the mean temperature and ozone mass mixing ratio inside the vortex, based on the fact that the Arctic vortex edge at the 50 and 10 hPa pressure levels is determined by the geopotential values, respectively, 19.5. 104 and 29.5. 104 m2 /s2 , using the ERA5 reanalysis data. The application of this method is justified for the Arctic polar vortex, which is characterized by significant variability, especially during the period of its splitting. The splitting of the polar vortex in 2009 was observed on January 24 and 28, respectively, in the middle and lower stratosphere. About a week after the splitting, the vortices became closer in characteristics to small cyclones, which completely collapsed within 1–3 weeks. The influence of planetary wave activity on the polar vortex does not always lead to its breakdown. Short-term splitting of the polar vortex is sometimes observed for several days after which the polar vortex strengthens again and PSCs form inside the vortex. Such a recovery of the polar vortex is most likely to occur in the winter. Based on the analysis of the dynamics of the Arctic polar vortex for 1979–2020 and using the example of the 2009 SSW, we showed that when the vortex area decreases to less than 10 million km2 and the mean wind speed at the vortex edge decreases below 30 and 45 m/s, respectively, in the lower and middle stratosphere, the polar vortex becomes a small cyclone (with significantly higher temperatures within it), which usually collapses within 3 weeks.

In the current context of climate change in the poles, one of the objectives of the APRES3 (Antarctic Precipitation Remote Sensing from Surface and Space) project was to characterize the vertical structure of precipitation in order to better simulate it. Precipitation simulated by models in Antarctica is currently very widespread and it overestimates the data. Sensitivity studies have been conducted using a global climate model and compared to the observations obtained at the Dumont d’Urville coast station, obtained by a Micro Rain Radar (MRR). The LMDz/IPSL general circulation model, with zoomed configuration over Dumont d’Urville, has been considered for this study. A sensitivity study was conducted on the physical and numerical parameters of the LMDz model with the aim of estimating their contribution to the precipitation simulation. Sensitivity experiments revealed that changes in the sedimentation and sublimation parameters do not significantly impact precipitation rate. However, dissipation of the LMDz model, which is a numerical process that dissipates spatially excessive energy and keeps the model stable, impacts precipitation indirectly but very strongly. A suitable adjustment of the dissipation reduces significantly precipitation over Antarctic peripheral area, thus providing a simulated profile in better agreement with the MRR observations.

The aim of this work was to generalize the known data and conduct experiments to determine the relaxation properties of ice in the ice cover under short-term (no more than 1 min.) loading. The problem lies in the fact that when one is solving applied problems of ice engineering, ice is often considered as an elastic isotropic material, and its stress-strain state (SSS) is studied in terms of the theory of bending of elastic plates. This does not allow performing theoretical calculations when resonant flexural gravity waves (IGW) are excited by moving loads, because under these conditions, the deflections of the ice increase to infinity and the known solutions become unusable. In fact, ice clearly manifests the properties of a quasi-isotropic medium, and the relationship between stresses and deformations is of a viscoelastic nature. It is noted in the work that, depending on the mode in which external loads act on the ice cover, its inelastic properties affect the nature of its behavior in different ways, while the viscoelastic properties of the ice cover are well described by the linear models of Maxwell or Kelvin-Voigt inelastic continuous media. The experimental material is duly processed and analysis is carried out of the results of experimental studies performed in the field by loading the ice cover with balanced loads using a specially made loading device, which was a frame with three supports. The design of the device made it possible to load the ice cover with balanced loads, which made it possible to exclude the influence of false elasticity of water on the results of experiments. For the rheological models of ice behavior indicated, the most probable ranges of changes in the relaxation times of stresses and deformations of the ice cover in the ice conditions considered are given. The results obtained can be used in theoretical studies of ice engineering problems.

The review generalizes experimental data on the relationships between the solar activity agents (space weather) and atmosphere constituents. It is shown that high-energy solar protons (SPE) make a powerful impact on photo-chemical processes in the polar areas and, correspondingly, on atmospheric circulation and planetary cloudiness. Variations of the solar UV irradiance modulate the descent rate of the zonal wind in the equatorial stratosphere in the course of quasi-biennial oscillation (QBO), and thus control the total duration (period) of the QBO cycle and, correspondingly, the seasonal ozone depletion in the Antarctic. The geo-effective solar wind impacts on the atmospheric wind system in the entire Southern Polar region, and influences the dynamics of the Southern Oscillation (ENSO).

The paper describes the GUSMP (North Sea Route Directorate) expert council session on the design of a powerful icebreaker of 18000–24000 HP held on June 15, 1935 in Leningrad, based on the archive documents. Analysis of the session materials sheds light on the state-of-the-art of icebreaker building in the mid-1930s. The standpoint of academician A.N. Krylov as well as GUSMP administration is particularly interesting.