Fabry-Perot Studies of Equatorial Thermospheric Dynamics and Composition

在该项目中，要求提供资金，以便利用在磁赤道以南约400公里的阿雷基帕运行的升级后的自动化阿雷基帕法布里-珀罗干涉仪观测台，继续研究赤道热层动态。 仪器升级FPI的灵敏度增加了15倍，实现了通过更换GaAs光电倍增管与背面减薄CCD探测器。 阿雷基帕FPI灵敏度的提高将用于扩大目前对午夜最高温度和赤道风和温度异常的研究，提高准确性。 提出了一条新的研究路线，将基于对O+和OH气辉发射的观测，用于热层[O]的研究。 O+光谱特征的多普勒宽度将提供关于1980年用这种技术观测到的热氧日冕可能产生的信息。如果这样的热[O]原子存在于赤道上热层和外底附近，除了有效多普勒宽度增加到相当于~4000 ℃的温度外，相对于由早期太阳俯角观测标准化的FLIP预测，应该看到732 nm发射率的几个瑞利数的过量。 建议的732 nm测量可以解决是否存在快氧离子从磁层流入赤道电离层的问题，这被认为是由磁极O+外流引起的，该外流被磁层转移到低纬度电离层-在夜间，将观测731.6 nm处OH夜光的多普勒频移，以确定OH体积发射平均的中间层风质心高度约为87 km的剖面。 这些结果将特别有助于支持TIMED（热层、电离层、中间层、能量学和动力学）卫星潮汐研究，因为对南半球中间层潮汐风的地面观测很少。 滤光片更换器将根据需要在630 nm和732 nm两种滤光片之间进行选择，以获得这些科学目标所需的观测结果。

In this project funds are requested to continue studies of the equatorial thermospheric dynamics using the upgraded automated Arequipa Fabry-Perot interferometer (FPI) observatory operating at Arequipa which is ~400km south of the magnetic equator. The instrumental upgrade increase of the FPI sensitivity by a factor of 15 is achieved by replacing the GaAs photomultipler with a back-thinned CCD detector. The improved sensitivity of the Arequipa FPI will be used to extend current studies of the midnight temperature maximum and the equatorial wind and temperature anomaly (EWTA) with increased accuracy. A new line of research is proposed that would be based upon the observations of O+ and OH airglow emissions for the study of thermospheric [O]. The Doppler widths of the O+ spectral feature would provide information regarding the possible production of the hot oxygen corona that was previously observed with this technique in 1980.If such hot [O] atoms exist near the equatorial upper thermosphere and exobase, aside from an increase in the effective Doppler width to equivalent temperatures of ~4000, an excess of a few Rayleighs of 732nm emission rate relative to the FLIP predictions normalized by the observations at earlier solar depression angles should be seen. The proposed 732 nm measurements may resolve the question as to whether there exists and influx of fast oxygen ions into the equatorial ionosphere from the magnetosphere, which has been suggested to be caused by the polar O+ outflow that is diverted to the low latitude ionosphere by magnetospheric-ionospheric coupling processes.During the night the Doppler shifts of the OH nightglow at 731.6 nm would be observed to determine mesospheric winds averaged over the OH volume emission profile with a centroid altitude of ~87km. These results would be particularly useful in the support of the TIMED (thermosphere ionosphere mesosphere energetics and dynamics) satellite tidal studies as ground-based observations of mesospheric tidal winds in the Southern hemisphere are sparse. A filter changer would select between the two filters, 630 nm and 732 nm, as necessary to get the observations these science objectives require.