Climatological study of GPS total electron content variations caused by medium-scale traveling ionospheric disturbances
Climatological study of GPS total electron content variations caused by medium-scale traveling ionospheric disturbances
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DOI：
10.1029/2005ja011418
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发表时间：
2006-04-22
影响因子：
2.8
通讯作者：
Saito, A
中科院分区：
文献类型：
--
作者：
Kotake, N;Otsuka, Y;Saito, A
使用从国际 GNSS 服务 (IGS) 获取的全球定位系统 (GPS) 数据，我们研究了与中等规模移动电离层扰动 (MSTID) 相关的总电子含量 (TEC) 扰动。我们分析了 3 年内（1998 年、2000 年和 2001 年）从 6 个地区（日本、欧洲、美国东部、美国西部、澳大利亚和南美洲）各 4 个或 5 个 GPS 接收器获取的 TEC 数据。为了导出 TEC (I') 的扰动分量，我们从每个卫星接收器对的 TEC 时间序列中减去 1 小时运行平均值。每小时计算 1 小时内 I' 的标准偏差，即 delta I，MSTID 活动定义为 delta I/(I) over bar，其中 (I) over bar 是绝对垂直 TEC 的 1 小时平均值。我们发现，在季节性、太阳活动、经度和纬度依赖性方面，白天的 MSTID 活动与夜间不同。所有六个地区的冬季白天 MSTID 活动都很高。另一方面，夜间 MSTID 活动的季节变化与其纵向变化相关。在日本和澳大利亚的纵向扇区，夜间MSTID在六月至日附近最活跃，而在欧洲纵向扇区，夜间MSTID在十二月至日附近最活跃。日本和澳大利亚纵向扇区的夜间 MSTID 活动与太阳活动呈负相关，而白天 MSTID 活动则不存在太阳活动依赖性。这些结果表明，导致 MSTID 的机制在白天和夜间可能有所不同。
Using global positioning system (GPS) data taken from the International GNSS Service (IGS), we investigated total electron content (TEC) perturbations associated with medium-scale traveling ionospheric disturbances (MSTIDs). We analyzed TEC data taken from four or five GPS receivers in each of six regions ( Japan, Europe, eastern United States, western United States, Australia, and South America) in 3 years ( 1998, 2000, and 2001). To derive perturbation components of TEC (I'), we subtracted the 1-hour running average form the time sequence of TEC for each satellite-receiver pair. Standard deviation of I' within 1 hour, delta I, was calculated every hour, and MSTIDs activity were defined as delta I/(I) over bar, where (I) over bar is the 1-hour average of absolute vertical TEC. We found that MSTIDs activity during daytime is different from that during nighttime with respect to seasonal, solar activity, longitudinal, and latitudinal dependences. Daytime MSTIDs activity are high in winter in all six regions. On the other hand, seasonal variation of nighttime MSTIDs activity is coupled with its longitudinal variation. In the Japanese and Australian longitudinal sector, nighttime MSTIDs are most active near the June solstice, whereas it is most active near the December solstice in the European longitudinal sector. Nighttime MSTIDs activity at the Japanese and Australian longitudinal sector shows negative correlation with solar activity, whereas solar activity dependence is not seen in daytime MSTIDs activity. These results suggest that mechanisms causing MSTIDs could be different between daytime and nighttime.