Dayside enhancements of thermospheric O/N2 following magnetic storm onset
Dayside enhancements of thermospheric O/N2 following magnetic storm onset
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DOI：
10.1029/2000ja000096
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发表时间：
2001-08
影响因子：
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通讯作者：
T. Immel;G. Crowley;J. Craven;R. Roble
中科院分区：
文献类型：
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作者：
T. Immel;G. Crowley;J. Craven;R. Roble
一个经常观察到的热层风暴效应是在高纬度和中纬度地区原子氧相对于分子氮的减少。这些成分的变化导致受阳光照射的半球热层o1130.4 nm辐射的减少。包括动力学探索者1号（DE 1）自旋扫描极光成像仪在内的各种卫星仪器都观测到了这种减少。相比之下，本文重点研究了DE 1对地面130.4 nm日辉发射的增强效果。1983年2月5日一次地磁暴在1610ut发生后，在南半球中纬度地区的早晨扇区观测到O I 130.4 nm辐射增加了20%。oi 130.4 nm发射量的增加表明原子氧相对于分子氮的增加。亮度的增强与全球电离层探空仪网络观测到的大规模重力波的通过相吻合。2月1日至6日期间的TIMEGCM模拟补充了全球FUV图像和电离探空仪观测，为将电离探空仪和DE 1观测结合起来提供了一个框架。这里考虑的FUV变化的主要机制是：(1)磁场活动开始时发射的大规模重力波引起的早晨部分原子氧相对丰度的增加；(2)先前受影响的包裹向白天一侧的偏移。根据重力波效应和瞬态哈德利环流单元，对观测到的FUV特征进行了物理解释。这项工作代表了首次从轨道上的FUV成像仪探测到大规模重力波。
One frequently observed effect of thermospheric storms is the reduction of atomic oxygen relative to molecular nitrogen at high and middle latitudes. These composition changes lead to a decrease in thermospheric O I 130.4-nm emissions in the sunlit hemisphere. Such decreases have been observed by various satellite-based instruments including the Dynamics Explorer 1 (DE 1) Spin-Scan Auroral Imager. In contrast, this paper focuses on enhancements of the terrestrial 130.4-nm dayglow emission observed with DE 1. Following the onset of a geomagnetic storm at 1610 UT on February 5, 1983, an increase (>20%) in the O I 130.4-nm emission was observed at middle latitudes in the morning sector of the Southern Hemisphere. The increased O I 130.4-nm emission indicates an increase of atomic oxygen relative to molecular nitrogen. The brightness enhancement coincided with the passage of a large-scale gravity wave that was observed in measurements from a global network of ionosondes. The global FUV images and ionosonde observations are complemented by a TIMEGCM simulation of the February 1–6 period, which provides a framework for combining the ionosonde and DE 1 observations. The primary mechanisms for the FUV variations considered here are increases in the relative abundance of atomic oxygen in the morning sector caused by (1) the large-scale gravity wave launched by the onset of magnetic activity and (2) corotation of previously affected parcels onto the dayside. The investigation leads to a physical interpretation of the observed FUV features in terms of the gravity wave effects and a transient Hadley circulation cell. This work represents the first detection of a large-scale gravity wave from an orbiting FUV imager.