Early morning irregularities detected with spaceborne GPS measurements in the topside ionosphere: A multisatellite case study
Early morning irregularities detected with spaceborne GPS measurements in the topside ionosphere: A multisatellite case study
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DOI：
10.1002/2015ja021447
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发表时间：
2015-10
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影响因子：
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通讯作者：
I. Zakharenkova;E. Astafyeva;I. Cherniak
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文献类型：
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作者：
I. Zakharenkova;E. Astafyeva;I. Cherniak
我们目前的观测赤道等离子体泡（EPB）在顶侧电离层在清晨（05-08 LT）在2014年2月18日至19日的磁暴的恢复阶段。这种罕见的不规则性是在太平洋地区使用几颗低地球轨道（LEO）卫星上的GPS测量发现的。我们使用由三颗Swarm和一颗TerraSAR‐X卫星组成的多卫星星座，2月19日在同一地区飞行，高度约为500公里。2014年2月19日，在约11世界时至16-17世界时的几个连续轨道上观测到低地轨道GPS数据中的EPB发生，这表明：（1）有利于EPB生成的条件持续时间（小时）较长;（2）EPB的形成和演化跨越太平洋的大范围经度;（3）EPB区可能向西移动（伴随黎明）。在LEO GPS数据中登记清晨EPB得到了同时进行的现场（Swarm和DMSP（国防气象卫星计划））和地面（电离层探测仪和GPS）测量的支持。基于LEO的GPS技术被认为是在缺乏地面设施的地区研究顶部EPB的必要和有前途的数据源。此外，我们使用瞬发穿透模型和热层-电离层电动力学全球环流模型（TIE-GCM）来确定导致所观察到的现象的可能机制。模型模拟结果表明，在09-17 UT期间，由于黎明前/黎明扇区的扰动发电机作用，出现了具有增强的垂直等离子体漂移（~40-45 m/s）的区域。
We present observations of the equatorial plasma bubbles (EPB) in the topside ionosphere at early morning hours (05–08 LT) in the recovery phase of the 18–19 February 2014 geomagnetic storm. This rare type of irregularities was detected in the Pacific sector using GPS measurements on board several low‐Earth‐orbit (LEO) satellites. We use a multisatellite constellation consisted of the three Swarm and one TerraSAR‐X satellites, that on 19 February flew in the same region and at similar altitudes ~500 km. The EPB occurrence in the LEO GPS data was observed for several consecutive orbits from ~11 UT to 16–17 UT on 19 February 2014, which suggests the following: (1) rather long duration (hours) of favorable conditions for EPB generation, (2) formation and evolution of EPB over wide longitude range of the Pacific Ocean, and (3) possible movement of the EPB region in the westward direction (with dawn). Registration of the early morning EPB in LEO GPS data was supported by concurrent in situ (Swarm and DMSP (Defense Meteorological Satellite Program)) and ground‐based (ionosonde and GPS) measurements. LEO‐based GPS technique is found to be essential and promising data source to study the topside EPB over regions with lack of the ground‐based facilities. In addition, we use the Prompt Penetration Model and the Thermosphere‐Ionosphere Electrodynamics Global Circulation Model (TIE‐GCM) to identify the possible mechanisms responsible for the observed phenomenon. The model simulation results indicate the occurrence of the zone with the enhanced vertical plasma drift (~40–45 m/s) owing to the disturbance dynamo action in the predawn/dawn sector during 09–17 UT.