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1.
The results of instrumental studies of storm activity and parameters of lightning discharges in the south of the European part of the Russian Federation are presented. The features of spatial and temporal variations of thunderstorms and lightning parameters within a radius of 650000 km around the center of the lightning- detection network of the High-Mountain Geophysical Institute (Nalchik) covering the North Caucasus and the Black Sea coast are considered. The total number of thunderstorm days per year on the territory in question is approximately 239. The specific lightning susceptibility of the ground surface is approximately 6 discharges/km2 per year in the south and 2 discharges/km2 per year in the north. The share of terrestrial lightning discharges (positive and negative) on the territory is 12% of the total number of lightning; the share of cloud and intercloud discharges is 88%. According to these data, the share of positive discharges accounts for about 23% of the total number of the “cloud-to-ground” discharges. The average value of the electric currents is 13.5 kA in the negative lightning and 10.6 kA in the positive lightning. The parameters of lightning discharges over mountain terrain (altitude more than 1000 m) and over flatland terrain (altitude less than 1000 m) are considered separately. It has been found that the mean amplitude of the electric current of lightning discharges (regardless of polarity) amounts to approximately 9.29 kA over the flatland regions of the North Caucasus and 11.24 kA in the mountain part; the median value of the amplitude of the electric current reaches approximately 6.56 kA over the flatland terrain and 7.99 kA over the mountain terrain. 相似文献
2.
A system of quasi-hydrodynamic equations for the electric field, charges, and concentrations of cloud particles and light aeroions in stratified regions of mesoscale convective systems is proposed and analyzed numerically in a one-dimensional approximation. The important role of Debye-charge layers, which are caused by light ions, is established. It is shown that, under certain aerodynamic conditions, both noninductive and inductive melting-related charging of particles may cause a narrow intense positive-charge layer to form near the zero-temperature isotherm; the altitude at which the vertical velocity component changes sign with respect to the height of the zero-temperature isotherm is of particular importance. When consideration is taken for an inductive charging mechanism and the real structure of the rising flow’s velocity, the distributions of charges and field strength (with a peak of about 100 kV/m), which describe the profiles observed in experiments, form in about 30 min. Taking into account the polarization of melting aggregates and water drops in an electric field when aeroions attach to them causes the rate of generating electric-charge layers to reduce. Thus, the solutions obtained in this study describe the structure and dynamics of spatially separated regions of electric charges in the stratified region and offer a satisfactory explanation for the experimental data. The results are important for explaining the abnormally high lightning activity of mesoscale convective systems, their role in initiating charges in the middle atmosphere, and maintaining the quasi-stationary state of the global electric circuit. 相似文献
3.
针对热带气旋(tropical cyclone,TC)闪电已有研究,首先从闪电活动分布特征、眼壁闪电爆发对TC强度和路径的指示、外雨带闪电活动与雨带对流结构的关系三个方面进行了总结;其次从动力-微物理方面对TC闪电的形成原因和特征机理进行了梳理;最后提出当前研究中存在的两个关键问题,并对后续研究内容进行了展望。基于地基和空基相结合的综合闪电探测得到的闪电属性特征参量,有望建立一个明确的、具有代表性的闪电活动-TC强度变化关系。利用沿海地区架设的三维闪电定位系统结合地基双偏振雷达,针对登陆台风强对流过程开展的综合观测研究,将有助于推进闪电观测资料在台风中小尺度强对流监测、预警和资料同化中的应用。 相似文献
4.
A. A. Evtushenko F. A. Kuterin E. A. Mareev 《Izvestiya Atmospheric and Oceanic Physics》2013,49(5):530-540
The suggested equation system, including 267 chemical reactions and corresponding parametrizations of disturbances of the electric field and electron temperature, describes the dynamics of the mesosphere composition under the influence of high-altitude discharges (sprites and halos). Based on this system, the ionic disturbance, neutral components, and optical emissions of the night mesosphere caused by the sprites were modeled for a height of 77–85 km. Most attention was paid to the dynamics of disturbances of concentrations of electrons and O 2 + , NO+, H3O+, H5O 2 + , and N 2 + typical of the studied heights. The major chemical reactions leading to the disturbance of ionic contents are determined and the relaxation dynamics of the chemical components is reviewed. The account of the excited atoms and molecules of nitrogen and oxygen allowed us to model the radiation of the sprite flash, calculate the volumetric velocity of the photon emission, and study the influence of the sprite on the neutral components of the mesosphere. 相似文献
5.
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. 相似文献
6.
S. P. Smyshlyaev E. A. Mareev V. Ya. Galin 《Izvestiya Atmospheric and Oceanic Physics》2010,46(4):451-467
A chemistry-climate model of the lower and middle atmosphere has been used to estimate the sensitivity of the atmospheric
gas composition to the rate of thunderstorm production of nitrogen oxides at upper tropospheric and lower stratospheric altitudes.
The impact that nitrogen oxides produced by lightning have on the atmospheric gas composition is treated as a subgrid-scale
process and included in the model parametrically. The natural uncertainty in the global production rate of nitrogen oxides
in lightning flashes was specified within limits from 2 to 20 Tg N/year. Results of the model experiments have shown that,
due to the variability of thunderstorm-produced nitrogen oxides, their concentration in the upper troposphere and lower stratosphere
can vary by a factor of 2 or 3, which, given the influence of nitrogen oxides on ozone and other gases, creates the potential
for a strong perturbation of the atmospheric gas composition and thermal regime. Model calculations have shown the strong
sensitivity of ozone and the OH hydroxyl to the amount of lightning nitrogen oxides at different atmospheric altitudes. These
calculations demonstrate the importance of nitrogen oxides of thunderstorm origin for the balance of atmospheric odd ozone
and gases linked to it, such as ozone and hydroxyl radicals. Our results demonstrate that one important task is to raise the
accuracy of estimates of the rate of nitrogen oxide production by lightning discharges and to use physical parametrizations
that take into account the local lightning effects and feedbacks arising in this case rather than climatological data in models
of the gas composition and general circulation of the atmosphere. 相似文献
7.
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. 相似文献
8.
S. V. Anisimov S. V. Galichenko N. M. Shikhova 《Izvestiya Atmospheric and Oceanic Physics》2012,48(4):391-400
The dynamics of the electric field in the planetary boundary layer (PBL) is thoroughly studied from in situ observations of
the aeroelectric field and the height profiles of the wind-velocity components in the conditions of temperature inversion
and incipient convection. It is established that the formation of a layer with temperature inversion is accompanied by a positive
trend in the intensity of the aeroelectric field and by the generation of short-period aeroelectric pulsations. The transfer
of a spatially nonuniform space charge and the formation of electrically active layers in PBL are studied by numerical modeling.
The response of the electric field to the motion of the space charges simulating the coherent structures of electrogasdynamical
turbulence is investigated for the vicinity of the observation point. The key parameters of the model distributions of the
space charge are analyzed. The linear dimensions of the model structures range from 20 to 500 m, and the density of the transported
charge varies from 0.1 to 1 nC/m3. The layer containing the model structures is located at a height of 60–300 m. It is shown that the spatial distribution
and the transfer of the space charge form the dynamical component of the aeroelectric field in the surface layer. The short-period
aeroelectric pulsations are induced by the transfer of the spatially heterogeneous space charge in PBL, while the positive
trend is due to the accumulation of the space charge below the inversion layer. When the inversion was recorded by a sodar,
the intensity of the field at the onset of the convection increased at a rate of 100 V/(m h) on average. 相似文献
9.
A. S. Kholodov M. O. Vasil’ev E. A. Molokov 《Izvestiya Atmospheric and Oceanic Physics》2011,47(1):87-107
The earlier developed monotonous conservative variant of a net-characteristic method of the second- and third-order approximation based on 3D equations of magnetic gasodynamics with consideration for the magnetic field diffusion is expanded for the solution of dynamic problems on the flow of the upper atmosphere of the Earth by solar plasma. It is modified, which results in support for the solenoidality of the magnetic field and the removal of the magnetic charge. Calculations are carried out and preliminary results of using software complexes to simulate the passage of the leading edge of solar plasma through the upper atmosphere of the Earth are given. Unlike existing studies in this direction, the dynamics of the passage of the leading edge upon a strong burst in the intensity of solar wind over the entire altitude range from the surface of the Earth to the upper magnetosphere is considered. 相似文献
10.
为了研究起伏海面对雷电电磁传播的影响,本文利用Barrick表面阻抗理论和Wait近似算法,采用改进二维分形海面模型模拟起伏海面,利用数值模式,分析起伏海面的雷电电磁传播特征,并进一步讨论了起伏海面对时差法闪电定位系统定位精度的影响。结果表明:起伏海面对垂直电场和磁场的峰值的影响不显著,但会引起波形的上升期时间的延长,浪高越大,影响越明显;随着观测距离的增加,雷电垂直电场波形的上升时间逐渐变长;风速的变化与雷电垂直电场波形的上升时间成正比;由于海面起伏引起雷电电磁场波形在传播中的变化会影响基于时差法闪电定位系统的定位精度,定位误差可达几至十几公里。 相似文献
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14.
P. A. Klimov G. K. Garipov B. A. Khrenov V. S. Morozenko V. O. Barinova V. V. Bogomolov M. A. Kaznacheeva M. I. Panasyuk K. Yu. Saleev S. I. Svertilov 《Izvestiya Atmospheric and Oceanic Physics》2017,53(9):924-933
In this paper, data obtained by the Vernov satellite are discussed in comparison with the data obtained by Universitetsky–Tatiana-1, 2 satellites. The advanced instrumentation onboard the Vernov satellite improved the capabilities of the data-transmission system, providing an opportunity to acquire more detailed information on transient atmospheric events (TAEs), including a wider range of TAE photon numbers (event brightness) down to lower photon numbers, the opportunity to observe the events in ultraviolet range without the considerable inclusion of red–infrared photons (which indicates the substantial contribution of electric discharges, lightning precursors, at the altitudes of thunderstorm clouds), and the observation of TAE series at a rate of about 10–100 occurrences per second with a period from tens of seconds to several minutes. 相似文献
15.
S. V. Anisimov S. V. Galichenko N. M. Shikhova K. V. Afinogenov 《Izvestiya Atmospheric and Oceanic Physics》2014,50(4):390-398
The electric state of the middle-latitude convective atmospheric boundary layer (ABL) is investigated during a point in time when it is not disturbed by clouds, precipitation, mist, or industrial aerosols. A numerical model is developed that estimates the electroaerodynamic state of the convective ABL. The model is parameterized using results of field observations and laboratory experiments. According to the model, vertical profiles of atmospheric electric field strength, space charge density, electric conductivity, and atmospheric electric current density are calculated in the horizontally homogeneous approximation with a high space-time resolution. 相似文献
16.
The dynamics of meteorological parameters, of sodar data on the temperature stratification of the atmospheric boundary layer, and of surface contents of pollutants (nitrogen oxides, carbon monoxide, and ozone) during the passage over Moscow of a structurally complex prominent cold front are discussed. It is shown that the cold front passage is accompanied by stepwise increases in the NO, NO2, and CO surface contents. A probable cause of this phenomenon is a quick entrainment of smoke plumes from high-altitude sources of pollution into the surface turbulent air near the frontal boundary. Intense advection of cold air at the rear of the cyclone can lead to the development of an unstable stratification in the atmospheric boundary layer even in the nighttime. Under these conditions, the minute-scale variability of contents of trace gases increases abruptly as compared to that occurring in the frontal zone of the cyclone prior to the passage of the front. This effect is statistically significant. The dynamics of surface ozone reflects an increase in its background concentrations in arctic air masses. 相似文献
17.
Parameters of radio pulses of cloud-to-ground multiple-stroke lightning discharges in Northeast Asia
Parameters of radio pulses from multiple-stroke lightning discharges arising on the territory of Yakutia and in Transbaikalia are estimated. The number of cloud-to-ground return strokes per lightning reaches 11, on average, 4.2 (without allowance for the cases of single lightnings) for Yakutia and up to 15 for Transbaikalia. The time interval between the subsequent strokes was on average 43 ms. A peak value of signals of subsequent strokes averages 0.5 of the value for the first stroke. 相似文献
18.
A theoretical problem of linear stationary disturbances of the background geostrophic flow of a stratified rotating medium (atmosphere) that are induced by inhomogeneities of the gravitational field is considered. There is a common belief that such inhomogeneities may only somewhat deform (distort) the state of hydrostatic equilibrium, but cannot affect the dynamics of the flow in the atmosphere. Generally, the problem statement is different for the processes over a solid surface and a water surface, because a water surface (the lower boundary condition for the atmosphere) is deformed by inhomogeneities of the gravitational field. The problem of disturbances over a water surface has been considered in recent papers of the authors; in this paper, the results are developed and significantly revised. The emphasis is on disturbances over a flat horizontal surface, which were not examined before. From the analytical solutions, it follows that the influence of inhomogeneities of the gravitational field on the atmospheric flows may be significant in some cases. Physical generation mechanisms of disturbances are analyzed. 相似文献
19.
The sea receives an enormous variety of wastes from direct discharges or, indirectly,from rivers or by rain or precipitation from the atmosphere. In some areas, toxic wastesaccumulate in sufficient quantity to create a threat to human health or to damagefisheries or other natural resources. It is necessary to be able to measure the effects ofpollution in the sea. This paper is concerned with the problems of assessing the impactof marine pollution on biological systems. 相似文献
20.
热带西太平洋大气气候基本态与厄尔尼诺期间赤道附近西风异常 总被引：6，自引：1，他引：6
利用合成分析的方法分析了自1961年以来观测到的8次厄尔尼诺事件中赤道西太平洋地区西风异常与大气气候基本态的关系,结果发现厄尔尼诺年赤道西太平洋地区西风异常具有和大气气候基本态相一致的季节变化特征.利用一个简单热带海-气耦合模式较好地模拟出了观测到的厄尔尼诺年赤道西太平洋地区西风异常的变化特征.对模式结果的分析表明,大气气候基本态对厄尔尼诺年赤道西太平洋地区西风异常的形成起重要作用,它是通过影响大气模式中的加热场来影响赤道西太平洋地区西风异常.大气模式中赤道太平洋地区的加热场的形成具有阶段性和地区性,在厄尔尼诺事件的初始阶段,大气气候基本态是大气模式中的加热场形成的主要因子,而在厄尔尼诺事件的发展和成熟阶段,赤道中东太平洋地区的海表温度异常(SSTA)是加热场形成的主要因子.模式模拟结果对大气气候基本态依赖的敏感性试验说明,在大气模式加热场中含有大气气候基本态的模拟中,沿中西太平洋赤道附近的纬向风异常表现出和观测类似的传播特征. 相似文献