Research On Measurement,Data Analysis And Application Of Three-Dimensional Atmospheric Electric Field

Atmospheric electric field is an important physical phenomenon in the field of atmospheric physics and space physics.The research on the measurement method and characteristics of atmospheric electric field has important theoretical and application value to improve the warning ability of lightning disaster,study the charge structure of thunderstorm cloud and guarantee the smooth progress of space activities.For a long time,people have thought the ground is an ideal conductor,and that the atmospheric electric field has only vertical component.However,the installation ground of atmospheric electric field meter is usually concrete,asphalt,soil and other media,which cannot be regarded as a good conductor.Based on this,this paper analyses the influence of ground dielectric constant on the three-dimensional components of atmospheric electric field,studies the measurement and sensor calibration methods of three-dimensional atmospheric electric field,and uses three-dimensional atmospheric electric field meter to observe the atmospheric electric field in different weather processes,which provides a new way for lightning warning and thunderstorm cloud charge model research.The main research contents and conclusions of this paper are as follows:(1)Based on the theory of electrostatic field,the variation trend of horizontal and vertical components of atmospheric electric field with ground dielectric constant and distance of thunderstorm cloud is analyzed.It is proved that the horizontal component of the ground atmospheric electric field in thunderstorm weather can not be ignored,which lays a theoretical foundation for the development of three-dimensional electric field meter.(2)Based on the traditional atmospheric electric field meter,a three-dimensional atmospheric electric field meter circuit is designed.In order to improve the accuracy and consistency of observation data,the calibration method of atmospheric electric field sensor is studied.The influence of structural parameters,sensor itself,plate tilt and defects on the uniform electric field of calibration platform is quantitatively calculated by analytical method.The basis for determining the calibration platform is put forward.If the diameter and spacing of the plate are 2D and 2d respectively,when the horizontal distance between the sensor and the edge of the plate is greater than 1.37 d,the electric field inhomogeneity will be less than 0.5%.If the equivalent diameter of the sensor is 2 r,the inhomogeneity of the electric field caused by the sensor will be less than 0.5% when the equivalent diameter and spacing of the plate are greater than 14.14 r.(3)The three-dimensional atmospheric electric field meter is used to observe the atmospheric electric field in different weather processes.It is concluded that the horizontal component of the atmospheric electric field is very weak in sunny days,and the diurnal variation of the vertical component has two peaks and two valleys.Aerosol and water vapor are the main causes of the diurnal variation,and their concentrations are positively correlated with the atmospheric electric field.During a rainy day with lightning,the peak value of the three-dimensional atmospheric electric field on the ground is positively correlated with the rainfall intensity,and the peak time of the electric field is ahead of the peak time of the rainfall intensity.The atmospheric electric field of a haze day has strong vertical and horizontal components,and the amplitude is positively correlated with the degree of haze.The vertical component changes negatively with the increase of haze.The magnitude and polarity of atmospheric electric field during thunderstorm weather can reflect the distance of thunderstorm cloud charge and the type of lightning occurrence.(4)A lightning warning method based on three-dimensional atmospheric electric field and multiple empirical mode decomposition(MEMD)is proposed.The feasibility of estimating the azimuth of charge center of thunderstorm cloud by three-dimensional atmospheric electric field is verified by experiments.The lightning warning is carried out by using the change of IMF energy and center frequency,and the data of Jiangsu Lightning Location System are used to verify the effect of warning.The statistical analysis shows that the detection probability is 76.2%,and the false alarm probability is 27.3%.Compared with the traditional threshold method,the false alarm probability is reduced by 14.4%.(5)Based on the multi-layer charge model of thunderstorm cloud,the functional relationship between three-dimensional atmospheric electric field and model parameters is established.The parameters such as the charge amount of each layer,the horizontal distance between thunderstorm cloud and observation point,and the height of charge center are inverted by using the observed value of ground electric field.Using the parameters obtained from the inversion,the atmospheric electric field values of several stations on the ground are estimated.The results show that the estimated values are close to the observed values of the actual stations.