| Lightning disaster is one of the ten natural disasters nowadays.Lightning warning and thunderstorm cloud location have an important impact on national economy,transportation,military,aerospace and other fields.Lightning early warning based on atmospheric electric field is an important means of lightning protection and disaster reduction.Therefore,research on atmospheric electric field measurement,especially three-dimensional atmospheric electric field measurement,lightning early warning and thunderstorm cloud location is the research focus and hot spot in the field of lightning detection.Atmospheric electric field is the basic parameter of atmospheric electricity and the basis of lightning warning.At present,the commonly used one-dimensional atmospheric electric field meter can only measure the atmospheric electric field in one direction,usually the vertical electric field,and can not determine the electric field vector.When the induction direction and the electric field direction are inconsistent,the measurement error is large.In application,thunderstorm charges need to be directed at airports and aerospace bases,and meteorological departments need to warn thunderstorm and its location.Therefore,the orientation of thunderstorm clouds is determined by detecting the intensity and direction of three-dimensional atmospheric electric field formed by thunderstorm cloud charges on the ground,and the trajectory of thunderstorm clouds is tracked.It has important theoretical significance and practical application value for analyzing lightning activity and charge structure of thunderstorm cloud and realizing directional lightning warning.In this paper,the distribution characteristics of three-dimensional atmospheric electric field on the ground of thunderstorm cloud are analyzed,and the relationship between the three-dimensional atmospheric electric field on the ground and the charge of thunderstorm cloud is studied.According to the requirement of the detection of ground electric field and the orientation of thunderstorm cloud,a three-dimensional atmospheric electric field sensor based on single-axis rotating disk is designed.A three-dimensional atmospheric electric field measurement system on the ground is constructed by combining the relative dielectric constant sensor.Through the design of calibration platform,the calibration method of electric field sensor is studied.The environmental conditions of field observation of three-dimensional atmospheric electric field measurement system are analyzed.Through field observation experiments,the properties and characteristics of three-dimensional atmospheric electric field on the ground are studied.Combining with radar images,the orientation of thunderstorm clouds is studied comparatively.A Lightning Orientation early warning method based on three-dimensional atmospheric electric field detection is proposed.The main contents are as follows:1.The distribution characteristics of three-dimensional atmospheric electric field generated by thunderstorm charges on the ground and the sensitivity of three-dimensional atmospheric electric field to ground dielectric constant and horizontal distance are analyzed.The relationship between the direction of electric field and the azimuth of thunderstorm clouds to observation points is studied.The orientation of thunderstorm clouds in the air is determined by combining the three-dimensional atmospheric electric field on the ground with the relative dielectric constant on the ground.2.The measurement principle of the atmospheric electric field sensor is studied,and a one-dimensional vibration shielded electric field sensor is designed.On this basis,a three-dimensional single-axis rotating plate atmospheric electric field sensor with differential signal structure is further designed,including sensor structure,induction electrode arrangement,induction signal processing circuit,system control circuit,storage and communication circuit,etc.According to the method of thunderstorm cloud orientation,the ground relative dielectric constant sensor with the same plane multi-electrode structure is designed.Combining with the three-dimensional atmospheric electric field sensor,the three-dimensional atmospheric electric field observation system is constructed.The lower computer measurement program and the upper computer processing software are designed.The experimental equipment is provided for directional observation of thunderstorm clouds.3.The calibration method of three-dimensional atmospheric electric field sensor is studied,the calibration device is designed,the influence of electric field on the induction electrodes of three-dimensional atmospheric electric field sensor in different directions is analyzed,the calibration scheme of three-dimensional atmospheric electric field sensor is determined,and the direction influence coefficient of three-dimensional atmospheric electric field sensor and the relative dielectric constant sensor of auxiliary measurement are calibrated.The calibration results were tested by experiments.4.The problem that the electric field measurement of three-dimensional atmospheric electric field sensor is susceptible to environmental impact is studied.The installation conditions of three-dimensional atmospheric electric field sensor and the general requirements for the surrounding environment are put forward.The thunderstorm cloud directional observation system is used to carry out long-term thunderstorm cloud directional observation experiments.According to the experimental data,the intensity characteristics of three-dimensional atmospheric electric field on the ground under different meteorological conditions,the characteristics of electric field intensity and electric field direction during the occurrence,development and dissipation of thunderstorm clouds,the change of electric field direction during the charge accumulation period of thunderstorm clouds and the change of electric charge structure during the lightning period are analyzed respectively.The system can be used to acquire the information of electric field intensity and direction of thunderstorm cloud and to orient thunderstorm cloud.5.The directional experiment of thunderstorm clouds is carried out by the direction of three-dimensional atmospheric electric field on the ground and the comparison and analysis of the directional effect of thunderstorm clouds with radar,it shows that the system developed in this paper can track the moving path of thunderstorm clouds.By setting the vertical electric field threshold of three-dimensional atmospheric electric field and combining the characteristics of electric field jitter,lightning is warned.At the same time,the direction of lightning activity is given by the horizontal azimuth of electric field.The experimental results are consistent with the observations of radar data and lightning location data. |
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