The variability estimates of the electric field potential gradient in an arid region of Southern Siberia are obtained from insitu measurements in the Shol tract (Tyva). The analysis of variations of the electric field, meteorological quantities, aerosol content and solar radiation in the surface layer during a sandstorm was carried out. During this phenomenon, three types of disturbances were noted in the surface electric field.
Estimates are obtained for the variability of atmospheric electrical quantities (electric field potential gradient and concentrations of positive and negative air ions) under electrically undisturbed atmospheric conditions. In-situ measurements were carried out in the mountainous and steppe landscapes of Khakassia and Tyva (Southern Siberia) during the warm period of 2022. A comparative analysis of the results obtained was carried out. The maximum concentration of positive air ions was recorded in the hilly steppe near salt lakes, the maximum concentration of negative air ions was recorded in the central part of the basin, and the maximum electric field potential gradient was recorded in high mountains.
The influence of the passage of mesoscale convective complexes (MCC) on γ-ray background and the meteorological quantities in the surface layer are presented in paper. It is noted, that the surface electric field reacts to the passage of the MCC earlier than other measured quantities. This temporary delay is 1 hour. After the rain ended, the elevated radiation background remained for more than 2 hours.
In the study, estimates of the variability of the surface electric field in undisturbed atmospheric conditions in Tomsk were obtained. It is noted, that the average and mode of the potential gradient in Tomsk under fair-weather conditions are ~280 and 250 V/m, and it is a typical range is 160–370 V/m. In the warm period of the year, the average and range of the potential gradient are 1.2 and 1.5 times, which less than in the cold period.
The slow variations of electric field potential gradient were investigated during the passage of mesoscale convective complexes (MCC) over the city of Tomsk. Variations of potential gradient during the MCC are characterized by prolonged periods of negative disturbance related with the passage of the base of the cloud system, which has mainly a negative charge, according to 31 cases. The positive disturbance has a shorter duration and is linked to the anvil. Variations of electric field potential gradient under the effect of MCC have an average duration of 2 hours and an amplitude of 12 kV/m.
The spatial and temporal variability of convective instability in the south of Western Siberia during the summer months of 1990–2019 was analyzed using Total Totals index values computed from ERA5 (ECMWF) data. For a 30-year period and specific decades, the spatial variability of the mean Total Totals values calculated for high atmospheric instability (by values above the 75th percentile) has been estimated. Centers with maximum values of the Total Totals index were localized for the 6, 9, and 12 UTC that approximately correspond to the beginning, maximum, and end of active convection under intra-mass conditions. The intra-decadal variability of the atmospheric convective potential was evaluated based on the Total Totals index over Western Siberia. Under changing climate conditions, the areas with the greatest changes in convective potential were identified.
It is noted that smoke plumes from remote forest fires bring, on the one hand, a significant decrease in the average values of the potential gradient of the electric field in the surface layer and, on the other hand – to a strong increase in their dispersion as compared with the "fair-weather" conditions. It is shown that the electric field decreases with an increase in the optical density of the smoke plume.
The results of studies of the consistent variability of the parameters of the electrode layer of the atmosphere during the passage of thick convective clouds accompanied by rainfall are presented. For a series of cumulonimbus cloud passes with heavy showers high-frequency (periods of less than 10 min) fluctuations in the structure of precipitation in time and size spectrum were analyzed. A correspondence between the variations of hydrometeors flow, electric field potential gradient (∇φ) and polar conductivities (λ±) has been established.
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