Том 60, № 6 (2024)
- Жылы: 2024
- Мақалалар: 8
- URL: https://journals.eco-vector.com/0002-3515/issue/view/13176
- DOI: https://doi.org/10.31857/S0002-3515606
Бүкіл шығарылым
Articles
Acoustic monitoring of internal gravity waves in the lower troposphere using an anti-hail acoustic cannon
Аннотация
The results of study of the influence of internal gravity waves (IGWs) on the spatial and temporal variability of the lower troposphere using a triangular network of three microbarographs and an anti-hail acoustic cannon installed in Talin (Armenia) are presented. By coherent analysis of pressure fluctuations measured at different points, the IGWs generated by thunderstorm cells about 5-6 h before the passage of the cells over the network of microbarographs were detected. The regularities of changes with time of phase speeds and directions of propagation of IGWs precursors of thunderstorms were studied. The possibility of monitoring of IGWs in the troposphere by measuring temporal fluctuations of the travel time of acoustic pulses along the ray-paths connecting the anti-hail cannon with spatially separated acoustic receivers has been demonstrated. Vertical profiles of wind velocity fluctuations in certain layers of the lower troposphere up to a height of 800 m were reconstructed from the shapes and travel times of acoustic pulses with a shock front scattered by a fine layered structure of wind velocity and temperature in the stably-stratified lower troposphere. Due to the high vertical resolution (of the order of 1 m) of the method of pulsed acoustic sounding of the lower troposphere used here, the vertical wavenumber spectra of layered inhomogeneities of wind velocity in the range of short vertical scales, from one to tens of meters, were obtained for the first time and theoretically interpreted.



Large-eddy simulation of a droplet-laden air-flow over a waved water surface
Аннотация
Large-eddy simulation of the dynamics of a turbulent, droplet-laden air-flow over a waved water surface has been carried out. Sufficiently small droplets (with diameter up to 300 micron) are considered which allows us to neglect their deformation. Collisions between the droplets as well as their evaporation are also not taken into account. The droplet mass fraction is prescribed sufficiently small, such that their impact on the air-flow is negligible; the surface wave is prescribed and not affected by either droplets or air-wind. Numerical model is based on the solution of three-dimensional, filtered over subgrid-scale fluctuations, Eulerian equations of air-phase motion, and thr Lagrangian equations of individual droplets motion. A turbulent-viscosity concept is employed for the closure for the subgrid stresses in the air-velocity equations where the kinetic energy of the pulsations unresolved by the mesh is determined by the solution of a prognostic equation. The model is verified by a comparison with the results of a direct numerical simulation of the full equations of motion of the air and dispersed phases. Phase-averaged profiles of the air velocity and momentum flux and droplet concentration for different Reynolds numbers of the carrier flow and droplet injection scenarios are obtained.



The high-resolving modelling of the M2 internal tide in the ice-free East-Siberian Sea: dynamics and energetics
Аннотация
Using the high-resolving version of the 3D finite-element hydrostatic model QUODDY-4, the fields of the dynamic characteristics (amplitudes of tidal elevations and ellipses of the baroclinic tidal velocities) at the pycnocline depth and the average (over a tidal cycle) depth-integrated components of the baroclinic tidal energy budget in the ice-free East-Siberian Sea have been presented. To the latters of them belong the density, the advective transport and the horizontal wave flux of baroclinic tidal energy, the mutual conversion rate of tidal energy and the dissipation rate of baroclinic tidal energy due to bottom friction. In the average (over a tidal cycle and the sea area) their values were equal to 1.7 × 103 J/m2, 11 and 269 W/m and 1.65 × 10–3 and 1.1 × 10–3 W/m2, respectively. These values are in general smaller than their analogs in the Laptev Sea.



Measurements of directional sea surface waves near Sakhalin Island by array of bottom station
Аннотация
Field measurements of sea waves are carried out off the coast of Sakhalin Island using an antenna of three bottom pressure sensors. The stability of statistical characteristics estimated by different devices in the antenna is analyzed. The probability distribution of wave heights qualitatively corresponds to the Glukhovsky distribution, but demonstrate a lower probability of high wave occurrence. The space-time spectra of waves are reconstructed. It is shown that the angular distribution of the spectral density of waves over two days of measurements is well described by the theoretical cosine squared distribution, and its width varies in the range of 50-90 degrees. The dominant direction of wave propagation is from the northeast. An independent method is proposed for estimating the local water depth using data from the antenna.



Satellite investigation of atmospheric gas composition
Аннотация
The gas composition of the Earth's atmosphere largely determines numerous weather and climate processes and phenomena. The importance of studying the composition of the atmosphere has stimulated the creation in recent decades of global and regional observation systems for water vapor, ozone and the substances depleting it, carbon dioxide and other greenhouse gases, and dozens of pollutant gases. A significant role in the global monitoring of the gas composition of the atmosphere is played by satellite observation systems, which make it possible to obtain regular, global and regional high-quality (in terms of accuracy and spatial resolution) data on its gas composition. The review is devoted to the analysis of modern remote satellite passive methods for determining the gas composition of the atmosphere and the main results obtained to date. A modern classification of passive and active satellite methods, the physical and mathematical foundations of passive methods, the main characteristics of the used orbits of space carriers and the types of geometry of satellite observations are given.
The advantages and disadvantages of various satellite passive methods using measurements of atmospheric transparency characteristics (eclipse method), Earth's own radiation, as well as reflected and scattered solar radiation are analyzed for various satellite measurement geometries in a wide spectral region from UV to radio waves. A brief history of the creation of special modern satellite equipment is given, as well as their characteristics — information content, altitude measurement ranges, errors and vertical resolution. Numerous results of global and regional monitoring of the atmospheric gas composition and examples of their use in various problems of atmospheric physics and climatology are presented.



Determination of total ozone column from spectral measurements of IKFS-2 during 2015–2022.
Аннотация
The results of determining the ozone total column (OTC) from the spectra of the outgoing thermal infrared radiation measured by the IKFS-2 instrument from the “Meteor-M” No. 2 spacecraft during 8 years of measurements are presented. The previously developed methodology for the interpretation of spectral measurements made in 2015–2020 with a scanning bandwidth (SBW) of 1000 km is applied to the measurements in 2021–2022 with SBW of 1500 km. It is shown that the observed increase in the differences between the IKFS-2 data and the results of independent measurements is caused not by the expansion of the OTC variability statistics, but by the increase in the range of scanning angle variation. After finalization of the methodology for the measurements with a 1500–km SBW, the comparison with independent data showed that the standard deviations of differences with the results of ground and satellite measurements for all 8 years do not exceed 3% and did not increase compared to the first 6 years of measurements. To analyze the results in the polar regions, the OTC values obtained from the IKFS-2 spectra are compared with the ozonesonde data, which are performed continuously throughout the year, including the polar night. A good qualitative agreement of the IKFS-2 data and ozone sounding data, including winter-spring periods of extreme OTC decrease at high latitudes of both hemispheres, is shown. The standard deviations of the differences between the IKFS-2 data and the OTC values from ozone sounding data were from 5.3 to 11 % (17–33 D.U.) for different stations, or on average for all stations 7.9 %, which is consistent with the uncertainty of the estimates of the integrated ozone content in the vertical column from ozonesonde data.



Aerosol time variations at middle atmosphere over Obninsk from data of lidar measurements
Аннотация
Results of lidar observations of middle atmosphere aerosol at 13–65 km altitude range over Obninsk city (55.1° N. 36.6° E) in 2014–2023 are presented. Season and yearly variations of aerosol are considered in dependence on layer altitude. Volcano eruptions mainly influence on yearly aerosol variations at lower 13–18 km layer. The role of photochemical processes increases at 24–30 km layer – summer maximum arises in season variations and yearly variations are observed in phase with the level of solar activity. At 45–65 km range aerosol origin is meteor one. Season variations change to inverse type – winter maximum and summer minimum arise. Yearly variations are observed in antiphase to the level of solar activity. The role of variety of factors influencing aerosol formation and conversion at 45–65 km layer is discussed.



The search for ice 0 in the Earth's atmosphere
Аннотация
In the last decade, it has been shown that in most cases atmospheric ice consists of a mixture of ices Ih and Ic, it is called ice with stacking disorder or stacking disordered ice Isd. In addition, it became known about the existence of another crystalline modification of ice, called ice 0. Ice 0 is a transitional form from deeply supercooled water to ices Ih and Ic, which form at temperatures below ‒23°C (at low pressures). For this reason, the question arose about the possibility of forming ice 0 in the structure of ice Isd. To clarify the issue, laboratory experiments were carried out to obtain layers of ice 0 on the surface of ice Ih, as well as dielectric measurements of the material of atmospheric ice from fallen hail. The results obtained confirmed the possibility of forming ice 0 in the structure of stacking disordered ice Isd. A special property of such a structure is the appearance of contact layers with high conductivity, which significantly changes the electrophysical characteristics of ice particles. For example, in particles of small sizes, resonances of plasmon oscillations arise, which affect the transfer of electromagnetic radiation in cloud formations. The study of electromagnetic properties of small ice particles containing ice 0, and their features in various areas of the atmosphere will allow solving a number of important tasks. These include refining the radiation balance of the Earth’s surface, thunderstorm phenomena, radiation transfer in cloud formations, and physicochemical processes in aerosols and snow covers.


