Ground and satellite observations of nighttime medium‐scale traveling ionospheric disturbance at midlatitude
Ground and satellite observations of nighttime medium‐scale traveling ionospheric disturbance at midlatitude
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DOI：
10.1029/2002ja009639
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发表时间：
2003-04
影响因子：
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通讯作者：
K. Shiokawa;Y. Otsuka;C. Ihara;T. Ogawa;F. Rich
中科院分区：
文献类型：
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作者：
K. Shiokawa;Y. Otsuka;C. Ihara;T. Ogawa;F. Rich
[1] 我们研究了2001年5月17日在日本滋贺县（北纬34.9°，磁纬25.4°）由气辉成像仪观测到的一次夜间中尺度行波电离层扰动（MSTID）。该结构在OI（630.0纳米和777.4纳米）的气辉图像中被识别为西北 - 东南向的带状结构（水平波长：230千米），以50米/秒的速度向西南方向移动。在滋贺县，通过法布里 - 珀罗干涉仪从630.0纳米发射的多普勒频移同时测量了中性风速度。根据这些参数，我们对由重力波和振荡电场产生的MSTID进行了模型计算。我们发现，对于重力波的情况，估计的垂直波长太小，无法解释观测到的气辉强度振幅。对于电场的情况，我们发现约1.2毫伏/米的电场振荡足以重现观测到的气辉振幅。这个模拟的电场与2001年5月17日我们观测期间国防气象卫星计划（DMSP）F15卫星经过滋贺县时观测到的电场相当。国防气象卫星计划的离子漂移数据显示，极化电场的振荡与气辉图像中的MSTID结构相关，这表明极化电场在MSTID的产生中起着重要作用。
[1] We have investigated a nighttime medium-scale traveling ionospheric disturbance (MSTID) observed by an airglow imager at Shigaraki (34.9°N, 25.4°MLAT), Japan, on 17 May 2001. The structure was identified in the airglow images of OI (630.0 nm and 777.4 nm) as NW-SE band structures (horizontal wavelength: 230 km) moving southwestward with a velocity of 50 m/s. Neutral wind velocity was measured simultaneously from the Doppler shift of the 630.0-nm emission by a Fabry-Perot interferometer at Shigaraki. From these parameters, we performed model calculations of MSTIDs generated by gravity waves and by an oscillating electric field. We found that for the case of gravity waves, the estimated vertical wavelength was too small to explain the observed amplitudes of airglow intensity. For the case of the electric field, we found that an electric field oscillation of ∼1.2 mV/m was sufficient to reproduce the observed airglow amplitudes. This modeled electric field was comparable to that observed by the DMSP F15 satellite as it passed over Shigaraki during our observing period on 17 May 2001. The DMSP ion drift data show that the oscillation of the polarization electric field correlated with the MSTID structure in the airglow image, suggesting that the polarization electric field plays an important role in the generation of MSTIDs.