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In the Arctic, climate warming is occurring several times faster than in other regions of the globe. This сan be the result of strengthening feedbacks between climate and atmospheric composition. However, there are very few data on changes in the concentration of climatically active substances in this region. Therefore, to fill the gap in data on the vertical distribution of gas and aerosol composition of the air over the Russian Arctic, an airborne survey of the atmosphere and water surface over the all Russian seas of the Arctic Ocean was performed with use of the Tu-134 Optik aircraft laboratory in September 2020. This paper analyzes the spatial distribution of gas and aerosol composition in the Arctic troposphere. It is shown that during the experiment, the CO₂ mixing ratio changed from west to east in the opposite direction in the near-water and boundary layers compared to the free troposphere (FT), namely, it was increasing in the planetary boudary layer (PBL) and was decreasing in the FT. The methane content in the near-water layer decreased in the same direction. Concentrations of CO, NO _X , and SO₂ in the Russian Arctic were very low, which is typical for remote background areas. All aerosol fractions also showed a decrease in their content from west to east.

The results of experiments on determining the turbulence parameters of a stratified atmospheric boundary layer using remote sensing are presented. The height-time distributions and vertical profiles of the dissipation rate of kinetic energy of turbulence and the structural constant of turbulent fluctuations of temperature obtained from measurements of radial velocity with a coherent wind lidar and temperature with a microwave radiometer are compared with altitude variations in the parameters characterizing atmospheric stability. It is shown that the dissipation rate, which determines the intensity of wind turbulence, decreases in the boundary layer with altitude for all types of thermal stratification. The intensity of turbulent fluctuations of temperature depends to a greater extent on altitude variations in thermodynamic conditions in the atmosphere. If the thermal instability of the atmosphere at higher altitudes exceeds that in lower layers, then the structural constant of temperature fluctuations can not decrease but increase with altitude. In accordance with the altitude variation in the structural constant of temperature, the values of the structural constant of turbulent pulsations of the refractive index can also increase with altitude and differ from those predicted on the basis of known models.

Ozone is one of the important trace gases of the Earth's atmosphere. This study anal yses ground-based synergetic MW + IR method for remote measurements of ozone using ground-based instruments at Peterhof (SPbSU) - MW ozonometer and Bruker IFS-125HR Fourier transform infrared spectrometer. Numerical estimates of the errors and vertical resolution of remote measurements showed that uncertainties of remote ozone measurements at different altitudes vary from 5 to 20% or more. The vertical resolution of the MW + IR method varies from ~ 10 to ~ 12 km. These estimates demonstrate the potential for determining ozone in Peterhof using ground-based combined MW and IR measurements.

The spatiotemporal distribution of the intensity of bioluminescence formed by hydrobionts in the Black Sea based on the data of expeditionary research conducted in June 2013 and September 2014 during the voyages of NIS “Professor Vodyanitskiy" (IBSS) was investigated. Comparison of this characteristic in the N-W and N-E parts of the Black Sea has been done. Satellite data on near-surface wind and geostrophic currents are used to explain the causes of spatiotemporal variations in the intensity of hydrobiont bioluminescence. It has been shown that in the vertical distribution of bioluminescence intensity, most stations had one maximum at the top part of the seasonal thermocline. At deep-sea stations in the north-western part of the sea located in the zone of weak vertical movements, two maxima were observed due to the development of heat-loving hydrobiont species in the upper maximum and cold-loving species in the lower one. The maximum values of the integral intensity of hydrobiont glow were observed in the divergence zone in the deep-water north-eastern part of the sea, which is explained by more active enrichment of waters with biogenic substances due to more intense upward movements. Obtained results can be utilized for more accurate assessment of the upper layer water bioproductivity in the Black Sea from satellite data.

The intensity and frequency of events associated with severe weather phenomena are currently increasing in Western Siberia. The Weather Research and Forecasting (WRF) atmospheric model makes it possible to study such phenomena, in particular, for warning about their occurrence. This article defines a set of WRF parameterization schemes that provide a full-fledged analysis of the causes of occurrence and monitor the further development of severe weather events. This set of schemes ensures correct operation of the WRF model under conditions corresponding to severe weather events. The paper details two weather events with such severe phenomena as very strong wind, very heavy rainfall, prolonged heavy rain, and abnormally cold wave, which occurred in Western Siberia on April 29-30, 2019, and December 25-26, 2020.

Solving of the light scattering problem of atmospheric ice crystals is necessary for the interpretation of laser sensing data of atmosphere. This article presents the results of calculating light backscattering matrices for ice atmospheric crystals of arbitrary shape. The number of faces for these particles is 15, 20, and 40 and the size range is from 10 to 300 mm. Calculations were carried out within the physical optics approximation for the case of arbitrary spatial orientation of particles and single light scattering. The wavelengths of the incident light are 0.532 and 1.064 mm. According to the statistical analysis of crystals, their optical properties slightly differ. It is shown that the optical properties of an etalon particle taken from the IAO SB RAS data bank is satisfied the above distribution. Thus, the results confirm the validity of using the database for the case of a large set of particles with the number of faces from 15 to 40. The results are necessary for constructing algorithms for the interpretation of data of lidar sounding of cirrus clouds.

Changes in the soil hydrothermal regime caused by the permafrost layer melting, represent the most important environmental factor in the dynamics of vegetation cover in the permafrost zone. The impact of soil melting on the growth index (GI) of larch ( Larix spp.) and on the gross and net primary productivity (GPP, NPP) of vegetation in the Arctic region of Central Siberia (open woodlands, tundra and forest-tundra) was studied. The following hypotheses were tested: (1) gravimetric data make it possible to estimate the water mass dynamics in soils; (2) thawing of frozen soils stimulates the growth of woody plants and the productivity of vegetation. The work used dendrochronology methods, field data, satellite gravimetry (GRACE survey) and GPP (Terra/MODIS survey). Analysis of gravimetry data revealed a significant long-term trend in water mass decreasing in soils of the permafrost zone (R² = 0.68). The amount of water released during melting is estimated at 6.4 ± 2.3 kg/m^-2 per year. A close connection was found between larch GI and GPP with moisture anomalies in soils (r = - 0.7 and r = - 0.9, respectively). The increasing temperature of the root layer and the moisture deficiency in water vapor also have a positive effect on the GI of larch and the vegetation GPP value in general (r = 0.6 and r = 0.6…0.9, respectively). It was found that pyrogenic carbon losses are significantly (by two orders of magnitude) lower than the NPP value. In conditions of waterlogging of soils, typical for the Arctic, climate warming is accompanied by an improvement in the hydrothermal regime of vegetation growth, promotes an increase in vegetation productivity and the permafrost zone maintains the status of a carbon sink area.

Changes in the productivity of Pinus sylvestris L. were analyzed by remote sensing (gross and net primary production/photosynthesis) and dendrochronology (radial trunk growth) methods on two different-aged forest plots of ribbon pine forests in the dry steppe of Western Siberia. For both plots (young reforestation plantings and natural forest) a significant positive trend of primary production volume change over the period 2000-2023 was revealed. Differences in the set of climatic factors limiting stand primary production volume (spring and fall temperature and precipitation) and radial growth of pine were determined (last September temperatures are significant for pine of different ages, the sum of annual precipitation and Selyaninov hydrothermal coefficient of the growing season are also significant for young trees, and June temperature is also significant for mature forest). Correlations between the width of annual growth of model trees and primary stand production in June and early July for natural forest and in the second half of June for plantations were established. Calculations of the annual volume of carbon sequestration by trees based on tree-ring and biometric data showed that on average over the last 5 years, pine in the table fraction deposited from 525 g C/year (young plantings) to 565 g C/year (mature trees). The results of calculations of carbon sequestration volumes (for single-age pine plantations) are comparable in absolute terms and correlate with the values of primary stand production obtained remotely.

Plant communities sufficiently change microclimate under their canopy. To reveal the effects of different types of herbaceous communities on the soil thermal regime, phytomass and soil temperature were measured in four plant communities of the Central Forest State Nature Bioshpere Reserve and its surroundings (Tver` oblast`). The productivity of the studied communities ranged in the order: abandoned meadows (930 ± 53 g/m²) - managed meadows (1111 ± 40 g/m²) - Filipendula ulmaria communities (1357 ± 155 g/m²) - subruderal tallherb communities (1726 ± 188 g/m²). The belowground phytomass in the 0-5 cm layer ranged on average from 614 ± 102 g/m² in the subruderal community to 1756±448 g/m² in the Filipendula ulmaria community. The total phytomass was positively correlated with the soil pH (R = 0.814, p < 0.001, n = 16), as well as with nutrient availability indicator values (R = 0.528, p = 0.029). In all the communities the temperature maximum coincided with that of air temperature and occur in June-July. In winter, soils at 8 cm did not freeze, but some days surface temperatures dropped below zero. Soil water capacity was significantly negatively correlated with mean temperatures at the depth of 8 cm in July, August, and September. The links with soil surface temperature were similar, but less pronounced. Soil temperatures at the peak of the growing season and in the following months were not significantly correlated with aboveground phytomass values. Thus, in the forest zone even within relatively small area the phytomass of herbaceous communities differs greatly. Soil temperature under herbaceous vegetation canopy mostly depends on soil physical properties, but not on aboveground biomass.

An effective system of Rhododendron yedoense var. poukhanense (H. Lév.) Nakai. regeneration from seedling explant based on the use of thidiazuron (TDZ) for meristem proliferation was presented. In vitro germinated seedlings were used as explants. The duration of seed germination was 24 days. The total germination of the R. yedoense var. poukhanense seeds of was at the level of 77.5 %. The effects of 4-hour TDZ pulse treatment (7.5; 15.0; 30.0 µM) with further transferring to Anderson’s medium (AM) without TDZ and direct cultivation on AM supplemented with 1.0 µM TDZ on the morphogenic potential of seedlings were studied. R. yedoense var. poukhanense regenerants obtained both after pulse treatment and after cultivation on a TDZ-containing medium ware found to require an additional passage on hormone-free AM (AM0) for elongation and an increase in the number of shoots per explant. The highest number of shoots per explant was obtained after elongation with direct cultivation on AM with 1.0 µm TDZ and after 30.0 µm TDZ pulse treatment, on average 9.32 and 10.32, respectively. The maximum percentage of rooted plants (50 %) was obtained under the action of 4-hour pulse treatment with indolyl butyric acid followed by in vitro cultivation on AM0. The presented study demonstrates for the first time the effect of various types of TDZ treatment on the proliferation and development of shoots, and the developed technology made it possible to obtain rooted and acclimatized microshoots induced by TDZ pulse treatment. As a result, R. yedoense var. poukhanense was included in the in vitro collection for conservation and propagation for further practical use.