全球电离层地图TEC数据的插值算法

由IGS工作组提供的全球电离层地图（GIM）是电离层重要的应用数据.卫星高度计能够提供全球实时的电离层延迟误差校正.利用GIM数据，以Jason-3时空分辨率进行电离层总电子含量（TEC）的时间维度插值和空间维度插值，其中空间维度插值采用了Kriging插值和双线性插值两种方法.针对两种插值方法得到的总电子含量，与平滑处理的Jason-3高度计cycle80双频延迟校正值转化的总电子含量进行对比分析.结果显示:其与Kriging插值的平均偏差为0.94TECU，均方根误差为2.73TECU，相关系数为0.91；与双线性插值的平均偏差为1.43TECU，均方根误差为6.85TECU，相关系数为0.61.这说明Kriging插值方法的精度明显高于双线性插值方法. 

Interpolation Algorithm of Global Ionospheric Map Product TEC

Global Ionospheric Map (GIM) is an important ionospheric data product provided by the IGS working group, which can provide global real-time ionospheric delay error correction for satellite altimeters. In this study, temporal and spatial interpolation of Total Electron Content (TEC) that derived from GIM data products was performed, with the temporal and spatial resolution of Jason-3 altimeter. Two spatial interpolation methods, Kriging interpolation and Bilinear interpolation, were used in this study. The TEC obtained by these interpolation methods is compared and analyzed with the TEC value that converted from the dual-frequency delay correction of the smoothed Jason-3 altimeter cycle80 data. Results show that the mean bias between Kriging interpolation and processed dual-frequency delay correction is 0.94TECU, the root mean square error is 2.73TECU and the correlation coefficient is 0.91. As a contrast, these statistics between Bilinear interpolation and processed dual-frequency delay correction are 1.43TECU, 6.85TECU, and 0.61, respectively. This demonstrates that the accuracy of the Kriging interpolation is significantly higher than that of the Bilinear interpolation.