地磁场极值预测及磁暴感应地电场有限元计算

基于兰州地磁台的地磁观测数据,利用基于广义帕累托分布(GPD)的超阈值模型对磁暴期间地磁场的水平分量值和分钟变化率进行拟合,并利用轮廓似然函数对地磁场重现水平进行了预测.通过对中纬度地区的5个地磁台重现值结果的综合分析,给出100年一遇和200年一遇的磁暴期间地磁场分钟变化率.利用大地电磁测深数据构建了华北地区三维电导...

Prediction of Geomagnetic Field with Extreme Value and Calculation of Geomagnetic Storm-induced Geoelectric Field Based on Finite Element Method

Based on the observation data from Lanzhou geomagnetic station,the paper uses generalized Pareto distribution(GPD)-based peak over threshold model to fit the data including the horizontal component of geomagnetic field during geomagnetic storms and the change rate on minute time scale,and uses profile likelihood function to predict the return level of the geomagnetic field.Through the comprehensive analysis on the return values of five geomagnetic stations in mid-latitude regions,the paper gives the change rate on minute time scale of the geomagnetic field caused by 100-year-recurrence-period and 200-year-recurrence-period geomagnetic storms.In addition,three-dimensional electrical conductivity model of North China is established with magnetotelluric data,and the distribution and strength of the geomagnetic field with different return levels is calculated using finite element method by taking the predictions of the return level as boundary conditions.