Inversion of Ionospheric O/N2 by Using FY-3D Ionospheric Photometer Data
WANG Da-xin1，2, FU Li-ping1,3,4*, JIANG Fang1，3，4, JIA Nan1，2，3，4, WANG Tian-fang1,2,3,4, DOU Shuang-tuan1,2
1. National Space Science Center，Chinese Academy of Sciences，Beijing 100190，China
2. University of Chinese Academy of Sciences，Beijing 100049，China
3. Beijing Key Laboratory of Space Environment Exploration，Beijing 100190，China
4. Key Laboratory of Environmental Space Situation Awareness Technology，CAS, Beijing 100190，China
Abstract：Space weather events such as magnetic storms can cause significant changes in the concentration of the neutral components O and N2 in the thermosphere. Therefore, the ratio of the column density of oxygen atom to nitrogen molecule O/N2 is often used as a sign of the ionosphere’s disturbance. The results have shown that the ratio of the density of O and N2 columns density O/N2 and the ratio of the column emission intensity 135.6/LBH of far ultraviolet airglow OⅠ 135.6 nm and N2 LBH have a good correlation, so far ultraviolet optical remote sensing is very important for monitoring space weather. Since the 1970s, research on ionospheric exploration with far ultraviolet airglow has been conducted abroad, and several related satellite coordinates have been launched, especially in the United States, Japan, Sweden and other countries. Among the airborne prediction and optical detection instruments operating in orbit, only some work in the microwave and visible wavelength, and there are no detection instruments working in far ultraviolet longer, until the successful launch of FENGYUN-3D meteorological satellite in November 2017. The ionospheric photometer on the satellite is the first airborne far ultraviolet airglow remote sensing detection load in China. It provides us with a series of far ultraviolet detection data with independent intellectual property rights, and lays a foundation for us to carry out the research of ionospheric O/N2 characteristics. Firstly, we described how to retrieve the ratio of column density O/N2 of the neutral component in the thermosphere by using the ratio of column radiation intensity 135.6/LBH. Secondly, in the msise-00 atmospheric model, the ratio coefficient between 135.6/LBH and O/N2 is calculated by AURIC, and then the ionospheric O/N2 is retrieved by using the far ultraviolet airglow data observed by ionospheric photometer in real time, which further verifies the disturbance of the ionospheric neutral component during the magnetic storm. In the process of data processing, Chebyshev filter is used to process the out of band stray light in the data, which further suppresses the influence of the stray light signal on the FUV spectrum signal. Finally, the inversion results of O/N2 retrieved by Ionospheric Photometer are compared with the results of Global Ultraviolet Imager (GUVI) loaded by foreign optical remote sensing. The results show that they have the same response to a magnetic storm, and the product RMS error of O/N2 is about 0.319 6. In this paper, we have made an initial analysis of the possible causes of the differences, which lays a foundation for the follow-up work. This studyis the first time to use the data of the far ultraviolet airglow remote sensing payload independently developed in China for data inversion and analysis, which is of great significance to the development of the ionospheric far ultraviolet remote sensing technology in China.
Key words：Ionospheric photo meter; Far ultraviolet remote sensing; The method of O/N2 inversion
[1] Paxton L J, Morrison D, Strickland D J, et al. Advances in Space Research, 2003, 31(4): 813.
[2] Meier R R. Space Science Reviews, 1991, 58(1): 1.
[3] Strickland D J, Evans J S, Paxton L J. Journal of Geophysical Research, 1995, 100(A7): 12, 217.
[4] Dymond K F, Budzen S A, Coker C, et al. Journal of Geophysical Research: Space Physics, 2016, 121(10): 10614.
[5] Morrison D, Paxton L J, Humm D C, et al. Proc SPIE, 2002, 4485: (hHPS://doi.org110.1117/12.454267).
[6] Zhang Y, Paxton L J. Journal of Atmospheric and Solar-Terrestrial Physics, 2008, 70(8-9): 1231.
[7] Eastes R W, McClintock W E, Burns A G, et al. Space Science Reviews, 2017, 212: 383.
[8] Stephan A W, Meier R R, England S L, et al. Space Science Reviews, 2018, 214(1): 42.
[9] Meier R R, Picone J M, Drob D, et al. Earth and Space Science, 2015, 2: 1.
[10] Strickland D J, Bishop J, Evans J S, et al. Journal of Quantitative Spectroscopy & Radiative Transfer, 1999, 62(6): 689.
