不同地磁活动下全球电离层产品的评估

Evaluation and analysis of global ionospheric maps under different geomagnetic activities

针对地磁活动会对电离层产品产生影响的问题,提出一种不同地磁活动下全球电离层产品的评估方法:通过评估6家电离层联合分析中心(IAACs)发布的全球电离层地图(GIM)总电子含量(TEC)数据在不同地磁活动条件下的精度,比较2018年地磁平静(8月19—24日)和扰动(8月25—30日)的2个时间段各个分析中心产品的差异。结果表明,磁暴期间,各个分析中心的平均全球总电子含量相对于平静期间可增加0.5个总电子含量单位(TECU)左右;同时磁暴期间的GIM产品精度降低,与全球定位系统(GPS)实测垂直总电子含量(VTEC)相比,各个分析中心模型均方根误差(RMS)可平均增大0.2个TECU,与詹森2号(Jason-2)测高卫星提供的VTEC相比,各个分析中心RMS可平均增大0.4个TECU;加拿大自然资源部门(EMR)和欧洲太空局(ESA)的产品受地磁扰动影响较大,欧洲定轨中心(CODE)的产品和IGS综合GIM的产品受地磁扰动影响最小;地磁扰动对各个分析中心的产品在低纬度地区和高纬度地区的精度影响较大,对中纬度地区的精度影响相对较小。

Aiming at the problem that geomagnetic activity has an impact on ionospheric products,the paper proposed an evaluation and analysis method of global ionospheric maps(GIM)under different geomagnetic activities:the accuracy of GIM total electron content(TEC)data from six Ionospheric Associate Analysis Centers(IAACs)under different geomagnetic activity conditions was evaluated;moreover,comparative analysis on the average global TEC of each analysis center’s product during two periods of geomagnetic quiet(from August 19th to 24th)and geomagnetic disturbance(from August 25th to 30th)in 2018 was carried out.Results showed that each analysis center's average global TEC would increase by about 0.5 total electron content units(TECU)during the geomagnetic storm;at the same time,the accuracy of GIM products would decrease during the geomagnetic storm,and the root mean square(RMS)error of the models would increase by 0.2 TECU on average compared with the global positioning system(GPS)measured ionospheric vertical total electron content(VTEC)data,and by 0.4 TECU on average compared with the VTEC provided by Jason-2 altimetry satellite;furthermore,Natural Resources Canada(EMR)and European Space Agency(ESA)products could be greatly affected by geomagnetic disturbance,while Center Orbit Determination Europe(CODE)products and IGS combined GIM products could be least affected by geomagnetic disturbance;in addition,geomagnetic disturbance would have a great influence on the accuracy of the products of each analysis center in low and high latitudes,but a relatively small effect on the accuracy of the products in middle latitudes.