The case of successive passage of two mesoscale convective systems (a mesoscale convective complex and a squall line) in the vicinity of Tomsk, which was observed on 26 June 2020 is analyzed. It is noted that the passage of the mesoscale convective complex corresponds to a sharp change in the structure of the vertical temperature profile and a high value of the vertical temperature gradient. The time interval that precedes the development of thunderclouds corresponds to the value of the vertical temperature gradient for the IMCES SB RAS territory – 2.18 °/100 m. Sudden changes in values from the positive vertical temperature gradient to the negative and vice versa correspond to the passage of the squall line. The data of the electric field potential gradient profile and the intensity of thunderstorm activity allow us to consider in more detail the dynamics of changes in the atmospheric boundary layer.
The spatio-temporal variability of the temperature of the lower atmosphere layer during the development of abnormally early thunderstorms and squalls in the southeast of Western Siberia on the example of the surrounding area of Tomsk is analyzed. It is noted that the highest density of lightning discharges during the event under study is not over the centers of the zones with the highest temperatures, but over their peripheral parts, where large contrasts of temperature changes are observed. The time intervals that preceded the development of storm clouds are correlated with the values of the vertical temperature gradient for the territory of the IMCES SB RAS – 2.2 º/100 m and 1.4 º/100 m for the village of Anikino.
Results of experimental and theoretical studies of the process of near-ground propagation of monochromatic acoustic radiation on atmospheric paths from a source to a receiver taking into account the contribution of multiple scattering on fluctuations of atmospheric temperature and wind velocity, refraction of sound on the wind velocity and temperature gradients, and its reflection by the underlying surface for different models of the atmosphere depending the sound frequency, coefficient of reflection from the underlying surface, propagation distance, and source and receiver altitudes are presented. Calculations were performed by the Monte Carlo method using the local estimation algorithm by the computer program developed by the authors. Results of experimental investigations under controllable conditions are compared with theoretical estimates and results of analytical calculations for the Delany–Bazley impedance model. Satisfactory agreement of the data obtained confirms the correctness of the suggested computer program.
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