利用最小二乘配置预报全球电离层总电子含量

GLOBAL IONOSPHERIC TEC PREDICTION BASED ON LEAST-SQUARES COLLOCATION METHOD

将全球电离层垂直总电子含量（VTEC）分解为非随机的系统部分和随机的信号部分,采用4阶自回归模型拟合滤波信号的自协方差函数,并基于最小二乘配置法原理,对全球电离层总电子含量进行长期预报和短期预报分析。结果表明,长期预报的系统部分与欧洲定轨中心（CODE）的全球电离层模型值之间的相关系数为0.812,模型拟合值与参考值残差在4 TECu以内。短期预报在南半球预报精度比北半球要低,地磁赤道南北纬20°区域和海洋区域预报精度最低。全球模型预报精度为1~7 TECu,北半球预报精度约为2.4 TECu,相比CODE方法提高约20.14%;南半球预报精度约为3.5 TECu,相比CODE方法略差;全球预报精度约为3.0 TECu,相比CODE方法提高约8.25%。

The global ionospheric model for long-term prediction and short-term prediction was analyzed through dividing the vertical total electron content（VTEC） into deterministic component and signal component, fit- ting the filtered signal of autocovariance function using 4-order autoregressive model, and using the Least-Squares Collocation method. The results show that correlation coefficient between long-term prediction of trend component and global ionospheric model of CODE is 0.812, and the residuals between model fitted values for daily mean global total electron content（ mean global TEC, MGTEC） and reference values are less than 4 TECu. The results of short- term prediction show that the prediction precision is lower in the Southern Hemisphere than that in Northern Hemi- sphere,and the prediction precision is the lowest in the region between 20~N and 20~S of geomagnetic equator and in the ocean areas. Global prediction precision RMS is about 1 -7 TECu ,the average precision is about 2.4 TECu in Northern Hemisphere,and is about 3.5 TECu in Southern Hemisphere.