Qian Liying, Gan Quan, Wang Wenbin, Cai Xuguang, Eastes Richard, Yue Jia
High Altitude Observatory National Center for Atmospheric Research Boulder CO USA.
Laboratory for Atmospheric and Space Physics University of Colorado Boulder CO USA.
J Geophys Res Space Phys. 2022 Jun;127(6):e2022JA030496. doi: 10.1029/2022JA030496. Epub 2022 Jun 17.
We examine characteristics of the seasonal variation of thermospheric composition using column number density ratio ∑ observed by the NASA Global Observations of Limb and Disk (GOLD) mission from low-mid to mid-high latitudes. We also use ∑ derived from the Global Ultraviolet Imager (GUVI) limb measurements onboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite and estimated by the NRLMSISE-00 empirical model to aid our investigation. We found that the seasonal variation is hemispherically asymmetric: in the southern hemisphere, it exhibits the well-known annual and semiannual pattern, with highs near the equinoxes, and primary and secondary lows near the solstices. In the northern hemisphere, it is dominated by an annual variation, with a minor semiannual component with the highs shifting toward the wintertime. We also found that the durations of the December and June solstice seasons in terms of are highly variable with longitude. Our hypothesis is that ion-neutral collisional heating in the equatorial ionization anomaly region, ion drag, and auroral Joule heating play substantial roles in this longitudinal dependency. Finally, the rate of change in ∑ from one solstice season to the other is dependent on latitude, with more dramatic changes at higher latitudes.
我们利用美国国家航空航天局（NASA）全球边缘和盘面观测（GOLD）任务在低中纬度到中高纬度观测到的柱数密度比∑，研究热层成分的季节变化特征。我们还使用了热层电离层中间层能量与动力学（TIMED）卫星上搭载的全球紫外成像仪（GUVI）边缘测量数据推导得出并经海军研究实验室MSISE - 00经验模型估算的∑，以辅助我们的研究。我们发现，∑的季节变化在半球上是不对称的：在南半球，它呈现出众所周知的年变化和半年变化模式，在春分点附近出现峰值，在至点附近出现主要和次要低谷。在北半球，它主要由年变化主导，有一个较小的半年变化分量，峰值向冬季移动。我们还发现，就∑而言，12月和6月至点季节的持续时间随经度变化很大。我们的假设是，赤道电离异常区域的离子 - 中性碰撞加热、离子拖曳和极光焦耳加热在这种经度依赖性中起重要作用。最后，∑从一个至点季节到另一个至点季节的变化率取决于纬度，在较高纬度变化更为显著。
