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Modern methods for predicting thunderstorms and lightnings with the use of high-resolution numerical models are considered. An analysis of the Lightning Potential Index (LPI) is performed for various microphysics parameterizations with the use of the Weather Research and Forecasting (WRF) model. The maximum index values are shown to depend significantly on the type of parameterization. This makes it impossible to specify a single threshold LPI for various parameterizations as a criterion for the occurrence of lightning flashes. The topographic LPI maps underestimate the sizes of regions of likely thunderstorm-hazard events. Calculating the electric field under the assumption that ice and graupel are the main charge carriers is considered a new algorithm of lightning prediction. The model shows that the potential difference (between the ground and cloud layer at a given altitude) sufficient to generate a discharge is retained in a larger region than is predicted by the LPI. The main features of the spatial distribution of the electric field and potential agree with observed data.

The database of the SABER/TIMED satellite campaign includes the reconstruction results of nighttime distributions of O, H, and some other characteristics at heights of the mesosphere–lower thermosphere from measurements of volume emission rate ofOH* profiles near 2 μm, temperature, and ozone. The retrieval procedure is based on the chemical equilibrium approximation of nighttime ozone and a model of two excited OH states (ν = 9.8) forming the indicated radiation. In this work, a modernized model of these levels with the corrected constants corresponding to published data is used to retrieve O, H, OH, HO 2 , and the chemical heating rate at altitudes of 80–100 km according to SABER/TIMED measurements in 2002–2021. It is found that the new parameters of the retrieval procedure lead to significant (up to 2 times or more) changes in the spatial distributions of O, H, and chemical heating rate, but only a slight change in OH and HO 2 distributions.

We study the effects of turbulence on the electrification of thunderclouds. Analytical estimates of the disturbances of electrical parameters (in particular, charging current) stipulated by turbulent effects are performed for different parameters of turbulence and hydrometeors. The obtained results are used to improve the parameterization of electrical processes. A detailed comparison of the results of numerical simulation of thunderstorm events with and without taking into account turbulent effects revealed some characteristic features in the change of the electric parameter distributions in a thundercloud. Various scenarios of the electric parameter variations due to taking into account a high level of turbulence in thunderclouds are found and analyzed. They are (i) general intensification of the electrical processes without any significant change in the structure of the electrically active areas; (ii) an increase in the electric potential near the maximum values with the simultaneous decrease in potentials at the periphery; (iii) an increase in the electric potential with the coalescence of nearby areas of the maximum values of the potential.

A new metal-polymer catalyst in a stable colloidal system, were prepared. Iron-paraffin catalysts, nano sized particles, with different polymers have been matrixes were used to examine the effects of polystyrene and their derivatives on chemical/structural properties through Fischer-Tropsch synthesis (FTS) and the yield as well. Nano size iron-containing particles distributed are suspended in the hydrocarbon medium of the slurry-reactor were found to have great impact and high percent conversion of CO to more than 70%. Polystyrene derivatives found to interact with Fe species by the formation of Fe3O4 oxide and amorphous hydrolyzed δ-FeOOH which were formed at the given conditions. All catalysts with a polymer found to have a bimodal distribution particle. In structural aspects, polystyrene derivatives increases the dispersion of Fe species and inhibits the coagulation of active iron particles, and on other hand, the chemical and structural effects would cause the increase of the FTS efficiency towered the selectivity of heavy hydrocarbons and olefins during the FTS. The state of iron and polymer-paraffin matrix were examined utilizing XRD and AFM techniques which showed the forms of ground state of iron as Fe3O4 oxide and amorphous hydrolyzed δ-FeOOH were exists. When the polystyrene derivatives are introduced, the proportion of amorphous paraffin found to be less than that in a crystalline state. The maximum conversion of CO (71%) and the yield of liquid hydrocarbons (63g.m-3) based on a cross-link polymer such as a polystyrene divinylbenzene (PS-DVB) used. A very interesting fact that the risen temperature found to have a small decrease in selectivity and an increase in conversion efficiency, this was observed in all reactions.

The contribution of turbulence to the electrification of thunderstorm clouds is considered for the first time using a model of the large-scale electric field generation in a weakly conducting media containing two fractions of colliding hydrometeors. The calculation results are compared with experimental data. It has been found that scenarios of electric-field generation and growth are significantly different for inductive and noninductive charging mechanisms. The range of thundercloud parameters (of conductivity and particle radii) for which the electric field grows exponentially in the case of inductive charging has been found. In the case of noninductive charging, it has been shown that the electric field strength grows linearly in time due to intensive fluctuations of the electric charge. The linear growth of the electric field can be a significant factor when approaching the threshold of the discharge initiation.

We study a method for increasing the efficiency of penetration of an intense electromagnetic wave into a layer of dense plasma. The method is based on the phenomenon of spatio-temporal synchronism of the nonlinear dynamic structures, which are excited in the layer, with the modulated wave incident on the layer. It has been established that in the case of a relatively weakly overdense plasma, the efficiency of constant-amplitude wave penetration into the plasma layer is determined by a single nonlinear parameter, namely, the ratio of the intensity of the incident radiation to the degree of plasma super-criticality, and increases with an increase in this parameter. It is found that a modulation of the amplitude of an incident wave, whose period is a multiple of the soliton generation period, can lead to a significant increase in the penetration efficiency.

​​​​​​​At the altitudes of the mesosphere–lower thermosphere, OH and HO2 play a significant role in many physicochemical processes. Thus, monitoring their spatiotemporal evolution, together with other chemically active trace gases, is one of the most important problems for this atmosphere region, in which direct measurements are difficult. This paper studies the nighttime OH and HO2 chemical equilibria using the 3D chemical transport modeling within the general approach, which includes the identification of the main sources and sinks in the equilibrium space–time areas and the derivation of analytical criteria for equilibrium validity. The presented analysis shows that there are extended areas where nighttime HO2 and OH are close to their local equilibrium concentrations, determined mainly by the reaction between HOx and Ox components among themselves and with H2O2, N, NO, NO2, and CO. In the upper mesosphere–lower thermosphere, the equilibrium expressions can be shortened so that they include the HOx–Ox chemistry only. These expressions describe the HO2 and OH equilibria from the top down to some boundaries, the altitude positions of which vary in the interval between 72–73 and 85 km and depend essentially on season and latitude. The developed analytical criteria reproduce the main features of these boundaries well almost everywhere. Due to weak sensitivity to uncertainties of reaction rates and other parameters, the criteria can be regarded as a robust instrument for HO2 and OH equilibrium validation. The obtained results allow us to extend previously proposed methods for the retrieval of poorly measured components from measurement data and to develop new approaches.

The assumption of nighttime ozone chemical equilibrium (NOCE) is widely employed for retrieving the Ox-HOx components in the mesopause from rocket and satellite measurements. In this work, the recently developed analytical criterion of determining the NOCE boundary is used (i) to study the connection of this boundary with O and H spatiotemporal variability based on 3D modeling of chemical transport and (ii) to retrieve and analyze the spatiotemporal evolution of the NOCE boundary in 2002–2021 from the SABER/TIMED dataset. It was revealed, first, that the NOCE boundary reproduces well the transition zone dividing deep and weak photochemical oscillations of O and H caused by the diurnal variations of solar radiation. Second, the NOCE boundary is sensitive to sporadic abrupt changes in the middle-atmosphere dynamics, in particular due to powerful sudden stratospheric warmings leading to the events of an elevated (up to ∼ 80 km) stratopause, which took place in January–March 2004, 2006, 2009, 2010, 2012, 2013, 2018, and 2019. Third, the space–time evolution of this characteristic expressed via pressure altitude contains a clear signal of an 11-year solar cycle in the 55∘ S–55∘ N range. In particular, the mean annual NOCE boundary averaged in this range of latitudes anticorrelates well with the F10.7 index with the coefficient of −0.95. Moreover, it shows a weak linear trend of 56.2±42.2 m per decade.

At the altitudes of the mesosphere-lower thermosphere, OH and HO.sub.2 play a significant role in many physicochemical processes. Thus, monitoring their spatiotemporal evolution, together with other chemically active trace gases, is one of the most important problems for this atmosphere region, in which direct measurements are difficult. This paper studies the nighttime OH and HO.sub.2 chemical equilibria using the 3D chemical transport modeling within the general approach, which includes the identification of the main sources and sinks in the equilibrium space-time areas and the derivation of analytical criteria for equilibrium validity. The presented analysis shows that there are extended areas where nighttime HO.sub.2 and OH are close to their local equilibrium concentrations, determined mainly by the reaction between HO.sub.x and O.sub.x components among themselves and with H.sub.2 O.sub.2, N, NO, NO.sub.2, and CO. In the upper mesosphere-lower thermosphere, the equilibrium expressions can be shortened so that they include the HO.sub.x -O.sub.x chemistry only. These expressions describe the HO.sub.2 and OH equilibria from the top down to some boundaries, the altitude positions of which vary in the interval between 72-73 and 85 km and depend essentially on season and latitude. The developed analytical criteria reproduce the main features of these boundaries well almost everywhere. Due to weak sensitivity to uncertainties of reaction rates and other parameters, the criteria can be regarded as a robust instrument for HO.sub.2 and OH equilibrium validation. The obtained results allow us to extend previously proposed methods for the retrieval of poorly measured components from measurement data and to develop new approaches.

​​​​​​​At the altitudes of the mesosphere–lower thermosphere, OH and HO2 play a significant role in many physicochemical processes. Thus, monitoring their spatiotemporal evolution, together with other chemically active trace gases, is one of the most important problems for this atmosphere region, in which direct measurements are difficult. This paper studies the nighttime OH and HO2 chemical equilibria using the 3D chemical transport modeling within the general approach, which includes the identification of the main sources and sinks in the equilibrium space–time areas and the derivation of analytical criteria for equilibrium validity. The presented analysis shows that there are extended areas where nighttime HO2 and OH are close to their local equilibrium concentrations, determined mainly by the reaction between HOx and Ox components among themselves and with H2O2, N, NO, NO2, and CO. In the upper mesosphere–lower thermosphere, the equilibrium expressions can be shortened so that they include the HOx–Ox chemistry only. These expressions describe the HO2 and OH equilibria from the top down to some boundaries, the altitude positions of which vary in the interval between 72–73 and 85 km and depend essentially on season and latitude. The developed analytical criteria reproduce the main features of these boundaries well almost everywhere. Due to weak sensitivity to uncertainties of reaction rates and other parameters, the criteria can be regarded as a robust instrument for HO2 and OH equilibrium validation. The obtained results allow us to extend previously proposed methods for the retrieval of poorly measured components from measurement data and to develop new approaches.