Sea ice charts produced by the ice services of the world are among the most widely used sources of information about sea ice conditions in the Arctic. The absolute majority of sea ice charts are based on visual expert analysis of satellite imagery accompanied by auxiliary data including ground information from coastal stations and ships navigating the Northern Sea Route (NSR). Ground measurements of sea ice thickness are necessary for validating the results of satellite imagery interpretation. Shipboard observations are highly valuable because, unlike coastal stations, the ships provide information about sea ice cover straight on the navigational routes, not in the coastal areas of land-fast ice, where the thickness values are not fully representative of the ice in the open sea. However, the current system of shipboard observations used by commercial fleets often does not meet the reliability requirements due to the human factor involved in the process of data collection. In the early 2000s, the Arctic and Antarctic Research Institute (AARI) suggested a new methodology for shipboard ice thickness measurement. A ship-based television complex (STC) was developed in order to exclude the human factor and standardize observations. The inaccuracy value was estimated as 3.8 % of the real thickness. By 2018, STC had been upgraded to a new ship-based television meteorological complex (STMC) allowing continuous automatic measurement of ice thickness and many other related hydrometeorological parameters during the entire voyage. The automatic and autonomous operation of the new equipment allows placing it on board the ship without the need for an ice specialist to be permanently present. It means that STMC can be used by commercial fleets, which constantly increase the number of Arc7 ice class vessels they use. For economic reasons, reinforced ice class vessels, whose number is growing, represent the only available infrastructure suitable for the deployment of distributed network providing operational hydrometeorological monitoring on the NSR. A comparison of STC data with AARI ice charts has revealed that real-time transmission of STC data from ships to the ice service office could increase the accuracy of ice charts and, as a consequence, the quality of the entire system of hydrometeorological informational support of maritime activities in the Arctic.

Sea ice is an important part of the Arctic climate system. In the recent decade, rapid changes in the sea ice conditions have been observed: sea ice extent and sea ice thickness are declining; conversely, ice drift speed and deformations are increasing [1–10]. The main aim of this paper was to describe the variability of sea ice conditions north of the Svalbard archipelago and analyze the changes occurring there. For most of the year, a stable polynya is observed north of the archipelago, which is commonly called “Whalers Bay”. The prevailing wind direction (8–9 months out of 12) is north-east, thus, almost throughout the whole year, conditions persist that support the flow of warmer Atlantic waters (AW) to the surface. Stable upwelling, together with the observed increase in AW’s temperature, contributes to the formation of the quasi-stationary polynya “Whalers Bay”. The ice conditions north of the Spitsbergen archipelago are changing extremely dynamically. However, all their diversity can be grouped into four main types. Type 1 — the area to the north of the archipelago is covered with ice; type 2 — the ice edge moves to the north of the archipelago; 3 — “Whalers Bay” polynya; 4 — an intermediate type, when a “passage” is formed to the Barents Sea between the ice edge and the northern coast of the archipelago. This study showed that since the mid-1990s the frequency of type 1 has significantly decreased, conversely, type 3 has become predominant, and the frequency of occurrence of type 2 has also increased. The maximum area of the polynya was observed in February 2012 and 2014, when the ice edge reached 82,5°N and 50°E, and 83°N and 46°E respectively. The lightest ice conditions were observed in 2012, 2013 and 2016. The main periods of 2–3, 5–6 and 14 years were identified in open water area variability. The ice cover to the north of the archipelago is largely presented by the conditions similar to the marginal ice zone with an actively changing ice edge configuration and the combined influence of factors characteristic of open sea areas and ice-covered areas. It is here that intense heat exchange takes place between the ocean and the atmosphere. The heat fluxes directed from the ocean to the atmosphere in the area of the polynya have increased by about 4 TW over the past 40 years. The highest correlation between the heat flux and the area of open water is observed with a lag of 2 months.

The Antarctic polar vortex forms in autumn, intensifies in the winter-spring period and decays in late spring. Inside the vortex in the lower stratosphere, favorable conditions are created for the annual spring ozone depletion. One of the conditions for the formation of the Antarctic ozone hole is the presence of a dynamic barrier along the vortex edge in the winter-spring period, which contributes to a decrease in temperature inside the vortex (necessary for the existence of polar stratospheric clouds) and prevents the penetration of air masses into the vortex. The dynamic barrier exists when the wind speed along the vortex edge in the lower stratosphere is at least 20 m/s. When the vortex area decreases below 10 million km2 , the dynamic barrier usually weakens, preceded by the vortex breakdown. The purpose of this work is to consider the relationship between the vortex area and the wind speed along the vortex edge using the Antarctic polar vortex as an example. To analyze the dynamics of the Antarctic polar vortex, we used a method based on vortex delineation, which makes it possible to calculate the vortex area and wind speed along the vortex edge using geopotential values determined from the maximum values of temperature gradient and wind speed and, thus, characterizing the polar vortex edges. Seasonal variations in the vortex area are mainly determined by the time of the beginning, peak and end of the polar night. In turn, seasonal changes in wind speed along the edge of the Antarctic vortex are additionally determined by the influence of the temperature of the lower subtropical stratosphere. To eliminate the influence of the seasonal variation, polynomial trends were removed from the time series of the parameters considered. We have shown that the relationship between the vortex area and the wind speed along the vortex edge can be traced for area values of less than 25 million km2 and more than 50 million km² . At small values of the vortex area (< 25 million km²), during its formation and destruction, a positive correlation appears between the vortex area and the wind speed along the vortex edge. At high values of the vortex area (> 50 million km²), a negative correlation can be traced between the parameters studied.

The article studies the presence and possible direction of climate change in Enderby Land, East Antarctica, where from 1963 to 1999, the only meteorological station of the WMO network operated at the Molodezhnaya research station (now the summer field base of the RAE), and now an automatic meteorological station has been installed. The trends in surface air temperature, wind speed and direction for the period from the mid-1960s to the present have been analyzed. As initial data, we used the results of ground-based observations at the Molodezhnaya station, as well as reanalysis datasets, which made it possible to complete the instrumental series and evaluate the dynamics of temperature and wind characteristics for the last decades. Monthly values of climatic parameters were used as initial values, but for wind characteristics presented as the V and U components of the speed vector, single values were taken, according to which the average monthly wind speeds and wind distributions in directions were estimated. From different reanalysis systems, by comparison with ground-based observations, series were selected that showed the greatest similarity in the dynamics of the climatic characteristics studied. Good agreement was found between the temperature series of observations at the Molodezhnaya meteorological station and the datasets UDEL_AirT, ERA5, and GISS. The correlation between the wind observation series is less strong; ERA5 reanalysis data shows the wind speed dynamics slightly better. According to the analysis of the long-term dynamics of average annual and monthly temperatures in the region of Enderby Land, the warming trend has not been statistically confirmed, however, a progressive increase in the number of months of the year with positive temperature dynamics has been noted. Based on the analysis of wind characteristics, it is shown that only an increase in average annual wind speeds of 0,1–0,3 m/s/10 years is statistically significant.

Summary The aim of the study is to estimate the role of sediment components in the accumulation of microelements in lakes of the permafrost-affected area (the Lena Delta, northern Siberia). A fractional analysis of several trace elements (V, Cr, Co, Ni, Cu, Zn, Sn, and Pb) was conducted. Samples were collected from 10 lakes during the summer period of the “LENA 2019” expedition. The content of the chemical elements in the sediments was measured with the ICP-MS instrument. The results of the work show a relatively homogeneous distribution of the acid-soluble forms of the metals in sediments from different lakes. The content of trace elements in all the lakes studied is determined by natural (lithogenic) sources. Stable minerals inherited from the rocks play a crucial role in the sediment formation. Most of the elements are predominantly fixed in stable mineral and organometallic fractions. However, for V, Co, and Cr a high level of geochemical mobility was identified in some of the lakes. The metals of soluble complexes are capable of migrating from the sediments to the water due to physical and chemical changes in the aquatic environment. Furthermore, the organic substances and the Fe/Mn hydroxides of the sediments have a low potential ability to bind the metals into stable compounds.

Solving the problem of developing the Arctic zone of the Russian Federation without causing irreparable damage to the environment requires monitoring its various components. The article discusses the need to create a network of systems for the observation of the state of water resources in the polar regions. It is shown that, along with the existing monitoring system for large water bodies and streams, it is necessary to create a program of facilitated research on small lakes and rivers, which are extremely numerous within the Arctic zone and extremely vulnerable to various types of anthropogenic impact. In developing a network of such observation systems, the main attention should be paid not to the state of specific objects, but to identifying negative trends in various parts of the Russian Arctic zone in order to timely prevent large-scale fresh waters disasters. It is proposed that the creation of the network should be based on the principle of landscape-hydrological zoning, which takes into account both the genesis of water bodies and the specific features of the functioning of aquatic ecosystems. After the zoning of the territory of the Russian Federation Arctic Zone is completed, it is recommended that observations be carried out at reference water bodies located within all the selected regions, taking into account landscapes, both at the regional and, in the case of a significant scale of anthropogenic impact, at the local level. Along with general observations that need to be carried out at all points, which will make it possible to obtain data on the features of hydrological and in-lake processes in various parts of the Arctic zone and compare their course, it is also necessary to develop special observations. The latter, developed within each selected region, must meet the requirements for identifying the features of regional processes and information support for mathematical modeling of emergency situations and the ecological crisis caused by the main types of anthropogenic activity. The information obtained on reference lakes and streams of a hydrological region may reveal negative processes occurring throughout its area and indicate the need for emergency measures.

In the Arctic Ocean (AO) of today, there are noticeable changes in the composition and structure of biological communities inhabiting the water-ice environment. Over the past two decades, a decrease in the number of species of the sea ice flora and fauna has been noted in the central regions of the AO due to the changing physical environment of their habitat. In view of the current climatic instability in the AO, it is important to monitor and evaluate their composition, structure and dynamics of development. It is also important to preserve the methods of processing the materials collected in order to compare the state of the water-ice biota on similar spatial and temporal scales of the basin. In the present study, centric and pennate diatoms dominating in ice floristic communities were selected as indicators of changes. The aim of the work is to analyze the physical state of the water-ice environment and the species composition of ice diatoms based on the materials of the expeditions within the NABOS program at the Research Vessel (R/V) “Akademik Treshnikov” in the Arctic Basin in 2018 and 2021. The field work included observations of the state of the sea-ice cover in the area of the expeditions, the selection of ice cores to assess the salt composition and species composition of the algae, as well as CTD-sounding of the under ice — water layer. The analysis of the materials collected showed significant differences in the species composition and abundance of algae between the seasons, which indicates the formation of independent floristic communities in the current conditions of unstable physical environment in the central regions of the AO, which confirms the previously obtained results in the period 2007–2015. The materials under discussion were obtained in a short period of time and in limited spaces in the zones of production of annual ice in the waters of the shelf seas and zones of removal to the central regions of the AO. At the same time, short-term observations provide “instant” information about the qualitative and quantitative state of sea-ice biological communities. In order to obtain reliable estimates, long-term observations are needed, which may be organized in the near future based on new logistical approaches to the study of the marine Arctic.