Relative Contributions of Ion Convection and Particle Precipitation to Exciting Large‐Scale Traveling Atmospheric and Ionospheric Disturbances
Relative Contributions of Ion Convection and Particle Precipitation to Exciting Large‐Scale Traveling Atmospheric and Ionospheric Disturbances
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DOI：
10.1029/2019ja027342
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发表时间：
2020-02
期刊：
影响因子：
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通讯作者：
C. Sheng;Yue Deng;Shunrong Zhang;Y. Nishimura;L. Lyons
中科院分区：
文献类型：
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作者：
C. Sheng;Yue Deng;Shunrong Zhang;Y. Nishimura;L. Lyons
在地磁活动时期，高纬度地区离子对流和粒子降水的增强对电离层和热层造成了很大的扰动。根据全球定位系统(GPS)的总电子含量(TEC)测量，由于行星际磁场(IMF)BZ南转和亚暴期间粒子降水增加，在2014年3月26日协调时间06：30至08：30 UT期间发现了大规模行进电离层扰动(LSTID)。来自全球电离层-热层模型(GITM)模拟的LSTID与GPS TEC测量结果的比较表明，总体上是一致的。用GITM进行了进一步的理论分析，讨论了离子对流和粒子降水对总焦耳加热以及由此产生的大尺度行进大气扰动(LSTADs)和LSTIDs的影响。结果发现，离子对流和粒子降水对总焦耳加热的贡献相当，但这两个强迫项引起的高度积分焦耳加热的变化可能表现出不同的分布。此外，由这两个强迫项引起的中性密度和TEC扰动的大小也是相似的。使用从该事件的全天成像仪测量得出的总能量通量与时间的关系来驱动GITM改进了LSTID的数据模型比较。然而，在LSTID的时间和TEC扰动的大小方面仍然存在数据模型差异，这需要进一步的研究和现实的事件特定规范。
During geomagnetically active times, the enhanced ion convection and particle precipitation at high latitudes cause substantial disturbances in the ionosphere and thermosphere. Large‐scale traveling ionospheric disturbances (LSTIDs) were identified from Global Positioning System (GPS) total electron content (TEC) measurements from 06:30 to 08:30 UT on 26 March 2014 as a result of southward turning of the interplanetary magnetic field (IMF) Bz and enhanced particle precipitation during a substorm. The comparison of LSTIDs from the global ionosphere‐thermosphere model (GITM) simulations with GPS TEC measurements shows a general agreement. Further theoretical analyses with GITM were conducted to sperate the influence of ion convection and particle precipitation on the total Joule heating as well as on the resulting large‐scale traveling atmospheric disturbances (LSTADs) and LSTIDs. It was found that ion convection and particle precipitation have comparable contributions to the total Joule heating, although the changes of height‐integrated Joule heating due to these two forcing terms may display different distributions. In addition, the magnitudes of neutral density and TEC perturbations due to these two forcing terms were found to be comparable. Using the total energy flux versus time derived from all‐sky imager measurements for this event to drive GITM improves the data‐model comparison of LSTIDs. However, data‐model discrepancies still exist in the timing of LSTIDs and the magnitude of TEC perturbations, which calls for further investigation and realistic event‐specific specifications.