Investigation on mesospheric gravity waves over Indian low latitude stations using sodium airglow observations and a few case studies based on thermal and wind structures
Investigation on mesospheric gravity waves over Indian low latitude stations using sodium airglow observations and a few case studies based on thermal and wind structures
复制标题
使用钠气辉观测研究印度低纬度站的中层重力波以及基于热结构和风结构的一些案例研究
DOI：
10.1016/j.jastp.2012.06.008
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发表时间：
2012
影响因子：
1.9
通讯作者：
A. Guharay
中科院分区：
文献类型：
--
作者：
S. Sarkhel;R. Sekar;D. Chakrabarty;A. Guharay
使用钠（Na）气辉光度计进行了系统的测量，从山。2006-2009年期间，在冬季和春季春分月的无云和无月之夜，Abu（24.6°N，72.7°E）和Gadanki（13.5°N，79.2°E）。Na气辉强度波动的周期范围从5分钟到3小时进行了分析，以确定系统的模式，如果有的话，在重力波模式，影响Na气辉发射。由钠气辉强度变化导出的功率谱。Abu和Gadanki揭示了15- 30分钟周期的常见现象，尽管光谱功率在这些站的较长周期处最大化。此外，还利用从TIMED卫星上的SABER和TIDI获得的几乎在这两个地方上空的中间层温度和水平风进行了一些案例研究。这一研究为重力波周期性与中间层中性不稳定性之间的可能关系提供了实验依据。基于案例研究，它表明，每当中性不稳定性发生在Na气辉发射层内，重力波的周期往往变得更短的周期相比，观察到的中性不稳定性发生时，超出Na气辉发射高度或不发生。
Systematic measurements using sodium (Na) airglow photometers were carried out from Mt. Abu (24.6°N, 72.7°E) and Gadanki (13.5°N, 79.2°E) during cloudless and moonless nights of winter and spring equinoctial months during 2006–2009. Na airglow intensity fluctuations with periodicities ranging from 5min to 3h are analyzed to determine the systematic pattern, if any, in the gravity wave modes that affect Na airglow emission. The power spectra derived from Na airglow intensity variation from Mt. Abu and Gadanki reveal common occurrence of 15–30min periodicities although spectral powers maximize at longer periodicities over these stations. Further, a few case studies were performed using mesospheric temperature and horizontal wind obtained from the SABER and TIDI onboard TIMED satellite nearly over both places. This investigation provides an experimental indication on the possible relationship between the gravity wave periodicities and the occurrence of neutral instabilities in mesosphere. Based on the case studies, it is shown that whenever the neutral instabilities occur within the Na airglow emission layer, the periodicities of gravity waves tend to become shorter in comparison with the periodicities that are observed when the neutral instabilities occur beyond Na airglow emission altitude or do not occur.