电离层薄层高度对电离层模型化的影响

利用IRI2012模型分析了电离层薄层高度的时空变化规律，提出了基于应用中STEC的电离层改正误差分析理论，分析了电离层薄层高度变化的相关影响.结果表明，电离层薄层高度变化对电离层穿刺点位置、投影映射函数值、电离层建模结果、电离层模型精化和电离层模型精度评估结果的影响较大.高度截止角为10°时，电离层薄层高度变化导致电离层穿刺点的经纬度差异最大可达3.2°，投影映射函数最高可引入约15.46%的误差，电离层建模结果差异和建模实用误差最高分别达9.71%，3.64%，采用不同薄层高度数据的电离层模型参数拟合和模型精化结果最大可引入约9.26%的误差，采用不同电离层薄层高度数据进行模型精度评定时最大可引入约9.62%的误差.根据这些研究结果可知:在实际应用中应采用电离层薄层高度模型，并选取较大的卫星高度截止角来减小薄层高度变化引入的误差；采用固定高度时，区域电离层建模采用与实际电离层薄层一致的固定高度；进行精度评估时，参考数据的电离层薄层高度与需要精度评估的电离层模型薄层高度相等. 

Effects of Ionosphere Shell Height on Ionospheric Modelingormalsize

The spatial-temporal variations of shell height are analyzed by utilizing IRI2012 model. The method for precision evaluation of the ionosphere models based on STEC differences in applications is presented, and the relevant influences of shell height on the positions of Ionospheric Pierce Point (IPP), mapping function, ionospheric modeling, ionospheric elaboration and ionospheric accuracy evaluation are discussed. When satellite elevation cut-off angle is set to be 10°, the shell height has important impact on the above quantities. The maximum deviation in latitude or longitude is about 3.2°. The maximum error of mapping function is about 15.46%. The maximum deviation and practical error are about 9.71%, 3.64% respectively. The maximum error in ionospheric elaborations is about 9.26%, and the maximum error in ionospheric accuracy evaluation is about 9.62%. According to the above results, the following suggestions are given. Firstly, a shell height model and a larger elevation cut-off angle should be adopted to reduce the above errors. Secondly, when a fixed shell height is adopted, the same height should be used in regional ionospheric modeling. Thirdly, the shell height of reference data should be the same to the be-assessed data in accuracy assessment.