A comparative study of TEC response for the African equatorial and mid-latitudes during storm conditions
A comparative study of TEC response for the African equatorial and mid-latitudes during storm conditions
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DOI：
10.1016/j.jastp.2013.05.008
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发表时间：
2013-09
影响因子：
1.9
通讯作者：
J. Habarulema;L. McKinnell;D. Burešová;Yongliang Zhang;Gopi K Seemala;C. Ngwira;J. Chum;B. Opperman
中科院分区：
文献类型：
--
作者：
J. Habarulema;L. McKinnell;D. Burešová;Yongliang Zhang;Gopi K Seemala;C. Ngwira;J. Chum;B. Opperman
研究太阳风对地球环境的影响，以了解其基本科学价值和对技术系统的重要实际影响。本文报告了2004年11月7日至12日连续两次电离层暴期间总电子含量（TEC）变化的结果，使用来自位于非洲赤道和中纬度的双频接收机的GPS数据。在地理坐标系中，赤道TEC变化被认为是在利伯维尔（0.36°N，9.67°E），加蓬和姆巴拉拉（0.60°S，30.74°E），乌干达。本文分析了南非萨瑟兰（32.38°S，20.81°E）和斯普林博克（29.67°S，17.88°E）中纬度站的TEC。通过比较从格拉姆斯敦（南纬33.30度，东经26.53度）和Madimbo（南纬22.4度，东经30.9度）电离层探空仪测量得到的F2层临界频率（foF 2）和F2层峰值高度（hmF 2）值，对南非上空风暴时电离层的变异性进行了分析。在分析的风暴期间，观察到中纬度地区的GPS TEC显著减少，foF 2相应减少，这是由于从其全球地图上观察到的GUVI O/N2比率减少。在赤道纬度，正风暴效应更占主导地位，特别是在风暴主相期间。在恢复阶段，在中纬度和赤道纬度都观察到风暴的负面影响。在磁暴期间观测到赤道TEC增强（从一个GPS站到另一个GPS站）的转移，部分归因于电离层移动扰动（TID）的通过。国际实时磁观测网络（intermagnet）站（阿迪斯，AAE（9.03°N，38.77°E））的磁强计数据被用来帮助解释在所分析的磁暴期间赤道电离层TEC动态的可能原因。
The solar wind effects on the Earth's environment are studied for their basic scientific values and crucial practical impacts on technological systems. This paper reports results of Total Electron Content (TEC) changes during two successive ionospheric storms of 7–12 November 2004 using GPS data derived from dual frequency receivers located at African equatorial and midlatitudes. In the geographic coordinate system, equatorial TEC variability is considered over Libreville (0.36°N, 9.67°E), Gabon and Mbarara (0.60°S, 30.74°E), Uganda. TEC over midlatitude stations Sutherland (32.38°S, 20.81°E) and Springbok (29.67°S, 17.88°E), South Africa are analysed. The analysis of the storm time ionospheric variability over South Africa was undertaken by comparing the critical frequency of the F2 layer (foF2) and the peak height of the F2 layer (hmF2) values obtained from Grahamstown (33.30°S, 26.53°E) and Madimbo (22.4°S, 30.9°E) ionosonde measurements. During the analysed storm period it is observed that GPS TEC for midlatitudes was depleted significantly with a corresponding depletion in foF2, due to the reduction in GUVI O/N2ratio as observed from its global maps. Over the equatorial latitudes, positive storm effects are more dominant especially during the storm main phase. Negative storm effects are observed over both mid and equatorial latitudes during the recovery phase. A shift in equatorial TEC enhancement (from one GPS station to another) is observed during magnetic storms and has been partially attributed to passage of Travelling Ionospheric Disturbances (TIDs). Magnetometer data over the International Real-time Magnetic Observatory Network (intermagnet) station, Addis Ababa, AAE (9.03°N, 38.77°E) has been used to help with the explanation of possible causes of equatorial ionospheric TEC dynamics during the analysed magnetic storm period.