Statistical study of medium-scale traveling ionospheric disturbances observed with the GPS networks in Southern California
Statistical study of medium-scale traveling ionospheric disturbances observed with the GPS networks in Southern California
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DOI：
10.1186/bf03352681
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发表时间：
2007-01-01
影响因子：
3
通讯作者：
Saito, Akinori
中科院分区：
文献类型：
--
作者：
Kotake, Nobuki;Otsuka, Yuichi;Saito, Akinori
利用2002年南加州350个双频GPS接收机的GPS数据，研究了时间分辨率为30 s、空间分辨率为0.15 ° x0.15 °的二维电离层总电子含量（TEC）扰动图，揭示了中尺度电离层行波扰动（MSTID）的统计特征。我们发现，MSTID可以分为三种类型。一种是白天的MSTID，经常发生在冬季和春分点。由于白天的MSTID大部分向东南方向传播，我们推测白天的MSTID可能是由热层中的大气重力波引起的。第二种类型是夜间MSTI，通常发生在夏季。夜间MSTD向西南传播。这种传播方向与极化电场在产生夜间MSTID中起重要作用的想法一致。第三种是黄昏型，夏季多发，向西北传播。黄昏MSTID可能是由起源于日落终结者的重力波引起的，因为它们的波前几乎平行于日落终结者。
Using global positioning system (GPS) data taken from 350 dual-frequency GPS receivers in Southern California in 2002, we investigated two-dimensional maps of total electron content (TEC) perturbations with a time resolution of 30 s and a spatial resolution of 0.15 degrees x0.15 degrees in longitude and latitude to reveal statistical characteristics of medium-scale traveling ionospheric disturbances (MSTIDs). We found that MSTIDs can be categorized into three types. One type is daytime MSTIDs, which frequently occur in winter and equinoxes. Since most of the daytime MSTIDs propagated southeastward, we speculate that the daytime MSTIDs could be caused by atmospheric gravity waves in the thermosphere. A second type is nighttime MSTIDs, which frequently occur in summer. Nighttime MSTIDs propagate southwestward. This propagation direction is consistent with the idea that polarization electric fields could play an important role in generating nighttime MSTIDs. The third is dusk MSTIDs, which frequently occur in summer and propagate northwestward. Dusk MSTIDs could be caused by gravity waves originating from the sunset terminator because they have wavefronts almost parallel to the sunset terminator.