Application and simulation of imaging Fabry-Perot interferometers to observe the upper atmosphere

Fabry-Perot interferometer (FPI);airglow emissions;atmosphericgravity waves (AGWs);satellite-basedFPI;thermospheric temperature and winds

Huang, Yiyi

关键词: Fabry-Perot interferometer (FPI);    airglow emissions;    atmosphericgravity waves (AGWs);    satellite-basedFPI;    thermospheric temperature and winds;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/31916/HUANG_YIYI.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Thermospheric temperature and winds are important parameters in the study of upper atmosphere dynamics. The Fabry-Perot interferometer (FPI) is a spectroscopic instrument which facilitates these measurements by observing the naturally occurring airglow emissions in the thermosphere. This dissertation focuses on the simulation and application of the FPI to study the upper atmosphere. A framework is developed, including a forward model based upon climatological and empirical models to simulate FPI observations andthe inverse process to estimate temperature and winds. We validate this framework by comparing the retrieved values of winds and temperatures to the known values inputted into the FPI simulation framework. The advantage of this framework is that it is applicable to both ground-based and satellite-based FPI simulations and allows for gradients in all of the parameters to be taken into account. Since the accuracy of FPI estimates depends greatly on the sky conditions, we then develop novel methods based upon FPImeasurements to remove data collected during cloudy weather. The methods described do not require a collocated imaging system or other instrument to determine sky conditions and, therefore, expand the useful database of windand temperature measurements. Two methods are developed, with the second one being a fully automatic algorithm. We then simulate several FPI scenarios using our framework to test the ability of FPIs to detect atmospheric gravity waves (AGWs). A two-FPI strategy shows a higher possibility for detecting an AGW when the two FPIs are observing common volumes in the upper atmosphere at orthogonal look directions. We show how periodogramanalysis can determine the frequency of the AGW. Finally, a satellite-based FPI scenario is simulated with look directions scanning downward. In this viewing geometry, we show that altitude-dependent temperature and windprofiles can be retrieved using an Abel-like inversion in the spectral domain.