Study On Global Lightning Intensity Based On Schumann Resonance

At present,the monitoring methods of lightning intensity mainly include the onboard optical detector(LIS / OTD),the VLF ground global radio detection network,and the ground ULF / ELF band electromagnetic inversion.The on-board optical detector can get the global lightning data,which is of great significance to the study of the global lightning distribution.However,due to the impact of satellite orbit,the global lightning distribution at the same time cannot be obtained,only through statistical methods to analyze.At the same time,the data is the lightning frequency at the satellite height,and cannot be directly obtained under the cloud.The lightning current intensity of.VLF global radio detection network needs thousands of receiving stations to cover the whole world.It has high detection cost,large interference and low detection efficiency.However,the loss of electromagnetic signal in the ground ULF / ELF frequency band is low.Only a few observation stations can cover the world,and the cost of observation is low.The main purpose of this project is to study and estimate the daily change of global background lightning intensity based on the ULF / ELF magnetic field data measured on the ground and simulated by the numerical model of the earth ionosphere waveguide.In terms of the parameter setting of the simulation data,considering the dynamic change of global lightning,combining with the lightning frequency data observed by the satellite,a strategy is developed to determine the location of global lightning and adopt the LM algorithm for the global lightning The ball lightning is inverted.The main research contents are as follows:(1)Firstly,based on the sampling data of ELF magnetic field observation from Yongsheng observation station in Yunnan Province,the Schumann resonance parameters are extracted by the method of row standing wave spectrum decomposition,and the daily variation curves of the first three resonance parameters are calculated and compared.(2)Secondly,the preliminary location of the lightning power source is extracted and the global lightning distribution in spring is preliminarily calculated.A narrow pulse with a maximum value of 1 is set to simulate the lightning discharge.A uniform cavity is used in the waveguide system.The parallel technology of MPI is introduced,which can save dozens of times by combining with FDTD method and calling related library functions.The electromagnetic response of the unit current pulse at different time and position is calculated.(3)Thirdly,based on the actual observed magnetic field power spectrum and the simulation power spectrum at different time and location,the LM algorithm is used to estimate the lightning current intensity at different time under the premise that the earth ionosphere system is a linear system.(4)Finally,based on the fitting weighting coefficient when estimating the lightning current intensity,the simulation magnetic field power spectrum of each time period at the observation station is obtained.Further,the resonance parameters of the simulation power spectrum are extracted by the line standing wave spectrum decomposition method and compared with the changes of the measured resonance parameters.