In this paper, the photochemical equilibrium of the odd oxygen and hydrogen families at altitudes of 50-80 km has been investigated via a three-dimensional chemistry-transport model. It is shown that there are wide enough ranges of latitudes, altitudes, and local times when the true concentration value of these families is in the ten percent vicinity of their instantaneous equilibrium values. In this case, the concentrations of these families can be considered to be in equilibrium and appropriate algebraic equations can be used to retrieve poorly measured minor mesospheric constituents, to validate measurement data, or to refine photochemical reaction constants.
The components of the mesosphere lower thermosphere region satisfy the algebraic relations resulting from the photochemistry. Applications of this relations to already self-sufficient measurements leads to a certain redundancy in form of functional relationship between the measured quantities. Airglow models are the key element in mesospheric measurements. The work considers the application of these relationships to satellite data series in order to improve airglow model (of excited hydroxyl). We investigate the problem in its general formulation. Using probabilistic approach we derive the method to determine airglow model coefficients analyzing long term observations. An upper estimate is made for the number of independently determined coefficients of the model.
KEYWORDS: Data modeling, Thermosphere, Mesosphere, Temperature distribution, Ozone, Chemical analysis, Atmospheric physics, Satellites, Air temperature, Ultraviolet radiation
The model of excited OH with constants corresponding to the published data was applied to retrieve nighttime distributions of О, Н, ОН, НО2, and the chemical heating rate at the altitudes of 80–100 km from the data of the SABER/TIMED measurements in 2021. The analysis revealed that the new parameters of the retrieval procedure result in significant changes in O, H, and the chemical heating rate, but not for the OH and HO2 distributions.
The conditions for the feasibility of the daytime photochemical equilibrium approximation of the odd oxygen (Ox) and hydrogen (HOx) families at altitudes of 50-80 km has been investigated with the use of analytical analysis and a onedimensional model. We proposed the criteria of their equilibrium. It’s shown that when the criterion is limited to 0.1, the difference between the true values of the concentrations of Ox and HOx and their local equilibrium values is approximately 10%. In this case, one can consider their concentrations to be in an equilibrium and use corresponding algebraic equations in different practical applications.
The revised model of excited OH with constants corresponding to the published data was applied to retrieve daytime O and H distributions at 77 km–100 km from the data of the SABER/TIMED satellite measurements in 2002–2021. It was found that changes of parameters in the retrieved procedure lead to (1) a noticeable (up to 30%) increase of the O concentration below 85-86 km, (2) a significant (up to 170%) increase of the H concentration below 90 km and a moderate (up to 40%) decrease near 100 km. The influence of revised O and H data on the retrieval of OH and HO2 is also analyzed.
The paper considers the effects associated with the influence of aerosols on the electric parameters of thunderclouds on the example of several thunderstorms in the Nizhny Novgorod region. The studies of the features arising when aerosol particles are taken into account are carried out using numerical simulation of thunderstorms with the use of the WRFARW model, supplemented by the parameterization of the electric processes, with two parameterizations of microphysics, one of which describes only hydrometeors, and the other also takes into account the presence of aerosol particles. The calculation results showed that the presence of aerosol particles affects both the microphysical and electrical structure of thunderclouds. It was found that in all the considered cases, accounting for aerosols led to an increase in the duration and scale of the thunderstorm.
We analyze the seasonal dependency of retrieval error in remote sensing problem while the quantity to be retrieved has seasonal evolution. In particular we estimate the seasonality in tropospheric measurements by HATPRO microwave profiler. For that we employ several methods: estimation using linearized retrieval procedure (employing error analysis), retrieval simulations, and direct comparison of real measurements with radiosonde data from the nearest aerological station.
The atmospheric boundary layer height is a key parameter characterizing this layer. The accurate evaluation of this parameter is critically important for almost all tropospheric research. Recently, remote sensing technique with the use of microwave passive radiometers is widely used for these purposes. IAP RAS performs continuous measurements of troposphere parameters (temperature and water vapor profiles) by the microwave profiler RPG HATPRO-G3. In this work, the dataset obtained during 2013 – 2018 is applied for determining the boundary layer height over Nizhny Novgorod. We compare the results with the estimation of boundary layer height from radiosonde data.
Measurements of atmospheric radiation over Nizhny Novgorod at the frequencies of the 5 mm band of molecular oxygen were carried out simultaneously with two devices: Spectroradiometer IAP RAS and RPG-HATPRO profiler. Comparison of the results at matching frequencies showed that the difference in the values of the measured brightness temperatures for a clear atmosphere in the zenith direction can reach 3 K, which significantly exceeds their variations during observation time. Such discrepancies should be taken into account when using these data to retrieval the troposphere temperature profile.
In this paper, we compared lightning activity over territories with different aerosol loads on the example of a megacity (Moscow), a metropolis (Nizhny Novgorod) and a sparsely populated area without large cities, but exposed to forest fires (central Siberia). The general patterns of thunderstorms during convective seasons, as well as the characteristic features of thunderstorms in each of the territories under consideration, are revealed. The analysis of the results of modeling the distributions of the electric potential for thunderstorms in the territories under consideration was carried out, which made it possible to identify differences in the electric parameters of thunderclouds for territories with different aerosol loads, which directly affect the occurrence of the electric discharges and lightning activity.
The feasibility of the daytime photochemical equilibrium of families of the odd oxygen and hydrogen at the altitudes of 50-80 km has been investigated via a one-dimensional model. It’s shown that if the permissible alterations between true values of the concentrations of these families and their instant-equilibrium values are limited to 10%, there are quite wide ranges of heights and local times in which we can consider the concentrations of these families to be in an equilibrium and use suitable algebraic equations to retrieve poorly measured minor constituents of mesosphere, validate measured data or refine constants of photochemical reactions.
On the example of the SABER/TIMED satellite data measured in 2003, we analyze the quality of daytime O and H retrieval at the altitudes of the mesosphere - lower thermosphere with the use of the condition of ozone photochemical equilibrium, which takes into account only the main chemical sink of this component due to photodissociation. It is shown that neglecting the reaction H+O3→O2+OH in this condition weakly manifests itself in the H distributions, but leads to a significant (up to 50-70%) systematic underestimation of the monthly mean and annually mean O distributions at the altitudes of 75-90 km.
A new approach for taking into account the impact of turbulence on thunderstorm electrification using the numerical model WRF-ARW is presented. For this, a method for calculating the turbulent energy dissipation rate on the basis of the radar reflectivity distribution and characteristic values of the turbulent energy dissipation rate in various types of clouds is developed. The charging current is corrected by the value of the turbulent current component determined for the obtained turbulent energy dissipation rate. Thus, calculation of the electric parameters (electric potential and electric field) of thunderclouds is carried out taking into account the influence of turbulent mixing on thunderstorm electrification.
We conduct an analysis of simultaneous measurements of microwave profiler RPGH-HATPRO and radiosonde which were obtained during 2013-2018 observation period. Using microwave data, we quantify the cloudiness of the conditions. We consider two datasets depending on cloudiness: moderate clouds and clear sky. The latter subset of the former. We investigate means and standard deviations of the difference between the temperature profiles retrieved from microwave data and radiosonde profiles. The seasonal means are at least two times the amplitude of whole dataset means. We discuss the reasons for observed behavior.
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