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This paper deals with new geological, mineralogical, geochemical (major, trace, and rare earth elements) and Sm-Nd isotopic data for the unique Kalevian (1923-1926 Ma) komatiite-tholeiite association for the first time identified in the supracrustal Kaskama Formation from the Inari Terrane of the Kola-Norwegian region Fennoscandian shield.

In the massive and porphyritic komatiites, the primary (magmatic) mineral paragenesis represented by olivine 20-40%, orthopyroxene up to 5%, hornblende up to 10%, clinopyroxene 20-40% and plagioclase 20-30% was identified.

Relic igneous minerals (olivine, pyroxene) make it possible to estimate (COMAGMAT3.73 program) their liquidus temperatures in the range of 1500-1200 °С.

The komatiites of the Kaskama Formation belong to the Al-nondepleted type and are characterized by a low level of REE_N content (1-2 relative to C1 chondrite), their total concentration (∑REE = 0.15-0.36 ppm) and an unfractionated distribution of REEs, which is a consequence of the generation and evolution of their primary melts outside the field of thermodynamic conditions of garnet stability.

The Zr–Y–Nb and Sm-Nd isotopic systematics of the rocks of the komatiite-tholeiitic association indicates the origin of their high-temperature primary melts from the plume source in depleted mantle (εNdT=+3.2±0.3), which is different from the mantle sources of the Jatulian-Ludicovian picrite-komatiite association of the Central-Lapland greenstone belt of Finland and the Pechenga intracratonic structure.

Considering the amphibolite facies metamorphic conditions of the Kaskama formation, it can be assumed that the komatiite-tholeiitic association is a deeply eroded (at least 10 km) section of the upper crustal volcanic apparatus.

Undertaked analysis of composition of the monzonite-sienite intrusive rocks, is abundant in the area of Bilikano-Khulamrinskaya magmatic zone of Central segment of the Yana-Kolyma orogenic belt. That rocks compose of small intrusions, which cut of terrigenous strata of Inyali-Debin turbidite terrane. That contained medium quantity of silica and Al₂O₃, relatively high – K₂O, Na₂O, MgO and chemically similar with latite. By chemistry that very close to alkaline felsic intrusive rocks of Aldan magmatic province. Balance concentrations of chemical elements, pointed out to belonging this rocks, to granitoids of convergent continental margin, include syncollision volcanic arcs. Age of that, by U‒Pb zircone dating (SIMS) 84 Ma, coincide with secondary impulse of magmatic activity of the Okhotsk-Chukotka Volcanic belt. Specific chemical composition of monzonite rocks of the Bilikano-Khulamrinskaya magmatic zone, close to shoshonite and latite, determined by location far in rear volcanic belt, at 200 km from axis zone of that, on the sialic basement, presented by turbidite sedimentary rocks.

Due to degradation of laser beam properties on atmospheric paths, the maximum length of communication lines is limited. In this regard, it is of interest to evaluate the possibility of detecting the topological charge of a vortex beam disturbed by atmospheric fluctuations using wave front sensors. The problem of measuring the wavefront tilts of a vortex laser beam propagating along a path in a turbulent atmosphere by a Shack-Hartmann sensor is considered. Estimates are obtained for the change in the angles of local tilts of wavefront associated with the solenoidal component of the Poynting vector and the influence of turbulent fluctuations of the refractive index of the atmosphere. Using several specific models of the Shack-Hartmann sensor as an example, the possibility of calculating the value of the topological charge of a vortex Laguerre-Gaussian beam from the measured angles of local wavefront tilts is investigated.

Based on the representation of the solution of the stochastic Helmholtz equation in the form of a path integral (Samelsohn G., Mazar R. Phys. Rev. E. 1996. V. 54, N 5) for the Kolmogorov model of the turbulence spectrum, an expression for the spatial coherence function of a spherical wave propagating in a turbulent atmosphere is derived under the assumption that the geometric-optical approximation is valid for a random phase incursion in the path integral. Estimates of the corrections to this approximation by order of magnitude are found. The obtained formula has no restrictions on the wavelength and the angle between the observation points that arise when using the parabolic and Markov approximations. The error in estimating the radius of spatial coherence in the parabolic approximation, arising from the sphericity of the wave front with an increase in the angular separation of the observation points, is calculated. It is shown that the error increases with the wavelength, and for millimeter and longer waves it can lead to an overestimation of the scale of spatial coherence of a spherical wave by few times.

Ergodic theorems are important when comparing measurement results with theoretical conclusions. Compilation of a “statistical ensemble" requires numerous experiments under similar conditions, which is practically impossible. Therefore, average values are necessarily derived from the measurement data of a single experiment by averaging the empirical data over a certain time range or spatial region. The question of how close such empirical averages are to probability averages is answered by so-called ergodic theorems. An ergodic theorem for stationary processes was proved by G. Taylor in 1922. In this work, we have proved an ergodic theorem for the case of non-stationary random processes. The proof confirms the ideas of O. Reynolds (1894), according to which the time averaging interval should be large compared to the characteristic periods of a pulsation field, but small compared to the periods of the averaged field. The cause of the drift of the mean value, which consists in the dependence of the average values of hydrodynamic fields on averaging interval length and significantly complicates the determination of empirical average values, is found. An approximate measure for quantitative assessments of this phenomenon is suggested; the existence of an averaging time at which the influence of this phenomenon is minimal is shown. The results are important for studies of atmospheric turbulence, where all hydrodynamic elements are non-stationary and show pronounced daily and annual variations.

Aerosol turbidity of the atmosphere over Antarctica is the lowest on the planet. However, it shows regional peculiarities in the temporal variability. In this paper, the main features of the interannual and seasonal variations in the aerosol optical depth (AOD) are revealed on the basis of the analysis of its long-term measurements at Mirny Station. Pronounced variations with a period of 5-6 years and amplitude of 0.005 relative to the average level of 0.023 in the interannual variability of AOD (0,5 mm) are shown. The annual variation in AOD of fine aerosol is characterized by spring and summer maxima (October and February), and that of coarse aerosol is characterized by one summer maximum. Approximation formulas are proposed that make it possible to estimate the monthly average values of spectral AOD in the wavelength range 0.34-2.14 mm.

Wind Doppler lidars have proven themselves as an effective means of evaluating wind turbulence in aircraft measurements. However, existing methods of sounding from aboard an aircraft assume the presence of a complex scanning system. In this work, we test possibility of evaluating turbulence parameters and wind convective flows using the second version of the lidar created in the Laboratory of Wave Propagation of IAO SB RAS during nadir sounding from aboard a flying aircraft. Based on the analysis of experimental data, we retrieved vertical profiles of estimates of vertical wind velocity (VWV) dispersion and turbulent kinetic energy dissipation rate up to altitudes of 1250-1600 m. During the analysis of sounding data near clouds, we recorded VWV shear according to one lidar signal spectrum, which contained two Doppler peaks. The results of this work can be useful in creating new methods for evaluating turbulence and wind shear.

Characteristics of a convective cloud with heavy rainfall over Saint-Petersburg and Leningrad region on 1st of July, 2023, are considered. The analysis was based on data of the weather radar DMRL-C, weighing precipitation gauges Pluvio² 200, and two lightning detection networks. The appearance and development of Cb under study was a result of merging two convective clouds. During their development the clouds slowly converged moving towards Saint-Petersburg from the southwest. Measurements have shown that the cloud merging led to explosive growth of the cloud top, which reached an altitude of 13.4 km; significant increase in the maximal reflectivity up to 69 dBZ, in volume of the cloud supercooled part with high reflectivity, volumes of the cloud with graupel and hail, precipitation intensity up to 140 mm/h, and lightning rate. The appearance of “the cloud bridge” was recorded. It has been shown that it consisted of graupel and wet snow particles.

Correct assessments of greenhouse gas fluxes and the global carbon cycle require well-provided data on greenhouse gas sources and sinks in the surface - atmosphere system at various natural sites. The article summarizes the results of shipboard measurements of carbon dioxide concentration in surface water throughout the water area of Lake Baikal received in eight spring campaigns of Limnological Institute, Siberian Branch, Russian Academy of Sciences. Spring period is of particular interest for research, since due to the large geographical extent of the lake from south to north, after the opening of the ice cover, the water gradually warms up. This makes it possible to take measurements in relatively different “seasons" during a time-limited expedition. Against the background of a noticeable interannual variability in the spatial distribution of CO₂ concentration in surface water in spring, its decrease from the Southern to the Northern basins of the lake is pronounced. While moving away from the coastal zone to the central part of the water area (to depths of more than 200 m), the concentration of dissolved carbon dioxide increases. The results of the study are of interest to specialists in climate issues and biologists, since carbon dioxide is one of the integral components of the carbon cycle during photosynthesis of aquatic plankton in the Baikal water.

Toxic waste from tailings dumps, as a result of erosion processes, can cause significant environmental damage through the migration of pollutants. This leads to the degradation of forest ecosystems, since heavy metal and arsenic compounds are absorbed by plants and soil. The purpose of the work is to assess the state of natural forest vegetation near a man-made source and determine the resistance of forest species in the stand and undergrowth to heavy metal pollution. To assess the state of natural vegetation, 4 test plots were laid taking into account the vegetation on strip counts. According to chemical analysis data, migration of heavy metals from the soil and litter to tree needles is noted. According to the assessment of the state of forest stands, 55 % of all studied species can be classified as weakened and drying out. The article provides an inventory characteristic of tree species and undergrowth near the Vysokogorskiy tailings dump on the territory of the Kavalerovskiy forestry of Primorskiy Krai. The obtained data on the state of the forest stand and the chemical composition of the components of the forest ecosystem made it possible to determine the resistance of various forest species to the impact of unfavorable factors.