Spatial-temporal Features Analysis and Partition Modeling of VTEC

Based on geostatistics principal,the global spatial-temporal partition features are investigated detailedly using IONEX products derived from IGS.Moreover,release policy of IONEX products is provided for IGS.Then,VTEC partition modeling methods which include both combination function method and IRI2007 background field method are presented.In the end,VTEC modeling results and analysis show that partition modeling greatly reduces the complexity of the model,and VTEC RMSE of low latitude partition B13 is invariably about two times that of high latitude partition A23 for two methods.So,VTEC partition modeling is proved to be effective and reliable.