Fabry-Perot Studies of Equatorial Thermospheric Dynamics and Composition

赤道热层动力学和成分的法布里-珀罗研究

• 批准号: 0132600
• 负责人: John Meriwether
• 金额: $ 24.25万
• 依托单位: Clemson University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-03-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0132600&HistoricalAwards=false
• 关键词: Fabry; Perot; Studies; Equatorial; Thermospheric

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.

在该项目中，将使用升级后的自动阿雷基帕法布里-珀罗干干仪（FPI）天文台继续研究赤道热层动力学，该天文台位于磁赤道以南约400公里处。仪器升级增加了15倍的FPI灵敏度是通过用后薄CCD探测器取代砷化镓光电倍增器实现的。提高了灵敏度的阿雷基帕FPI将用于扩展目前对午夜最高温度和赤道风和温度异常（EWTA）的研究，提高了精度。提出了一种新的研究方法，该方法将基于对O+和OH气辉发射的观测来研究热层[O]。O+光谱特征的多普勒宽度将提供有关热氧日冕可能产生的信息，这是1980年以前用这种技术观测到的。如果这样的热[O]原子存在于赤道上层热层和外基附近，除了有效多普勒宽度增加到~4000的等效温度外，相对于在早期太阳低压角观测归一化的FLIP预测，应该看到732nm发射率的几个瑞利。提出的732 nm测量可以解决关于是否存在快速氧离子从磁层流入赤道电离层的问题，这被认为是由磁层-电离层耦合过程导致极性O+流出转向低纬度电离层引起的。在夜间，将观测到731.6 nm处OH夜光的多普勒频移，以确定在质心高度为~87km的OH体积发射剖面上的平均中间层风。这些结果在支持TIMED（热层电离层中间层能量学和动力学）卫星潮汐研究方面特别有用，因为对南半球中间层潮汐风的地面观测很少。滤光片转换器将在630 nm和732 nm两个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。