The Research Of Neutral Wind And Temperature Retrieval From Nightglow Measurements By A Ground-based Fabry-perot Interferometer

The wind and temperature of the earth's thermosphere are key parameters for studying thermospheric storm and ionospheric storm caused by solar and geomagnetic activity and for understanding the dynamics and coupling between thermosphere and ionosphere.The upper atmosphere not only plays a crucial role in environmental prediction of the terrestrial space but also is a region where most satellites fly by.It is quite meaningful to detect and study the wind and temperature of the thermosphere from a scientific or practical point of view.Due to the difficulty of the detection and the lack of the data,the knowledge of them is very limited.Therefore,it is still an important hotspot in the research of the space weather.Fabry-Perot interferometer(FPI)is widely used in studying the upper atmosphere nowadays due to its high resolution and sensitivity.The spectroscopic instrument can obtain a series of fringes with bright and dark bands by observing OI 630.0 nm airglow emissions occurring in the upper atmosphere.The fringes contains the information of the wind-induced Doppler shift and temperature-induced Doppler broadening.The temperature and the wind velocity can be derived from these interference fringes.Three methods are used to derive neutral winds and temperature from mid-and upper atmospheric airglow measurements by a ground-based Fabry-Perot interferometer(FPI),which was deployed at Xinglong station(40.2 ° N,117.4 ° E)in Hebei province.The three methods are the radius method,the complete Fourier series description method and the nonlinear regression fitting method,respectively.The retrieval results show that the three methods can derive the neutral winds correctly,within a given range of error.the radius method is relatively simple,but it combines two observed fringes in different time and place to derive one result.Therefore,the retrieval error is large for the radius method.Compared with the FPI's owe speed results,the complete Fourier series description method and the nonlinear regression fitting method are very consistent with in a given range of error.Only the complete Fourier series description method and the nonlinear regression fitting method can derive the temperature,compared with the FPI's owe temperature results,although there are some differences that are less than 100 K between them.The two derived temperature datasets have the same trend in one day.The retrieval results of the wind velocity and the temperature show significant difference from HWM07 and MSISE-00 model simulaitons.The nonlinear regression fitting method is recommended in comparison with the other two methods,because more comprehensive fringe information is taken into account to derive neutral winds by this method.