China's First Infrared Occultation Spectrometer (GaoFen-5/AIUS) Monitoring Atmosphere Above Antarctic: Evaluation of Methane Profiles

• Published in: IEEE journal of selected topics in applied earth observations and remote sensing Vol. 17; pp. 7946 - 7956
• Main Authors: Liu, Shuanghui, Li, Xiaoying, Xu, Jian, Shi, Hailiang, Guo, Yuhang, Zhang, Xingying, Ge, Shule, Wang, Yapeng, Wang, Hongmei, Cao, Xifeng, Rao, Lanlan, Shi, Jiancheng
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Absorption spectra; Algorithms; Antarctic; Antarctica; Atmospheric measurements; Atmospheric monitoring; Extraterrestrial measurements; GaoFen-5 (GF-5)/atmospheric infrared ultraspectral sounder (AIUS); Gases; Greenhouse gases; Infrared absorption; Infrared spectra; Infrared spectrometers; Instruments; Mathematical models; Methane; methane (CH<named-content xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" content-type="math" xlink:type="simple"> <inline-formula> <tex-math notation="LaTeX"> _{4}</tex-math> </inline-formula> </named-content>); methane (CH<named-content xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" content-type="math" xlink:type="simple"> <tex-math notation="LaTeX">$_{4}$</tex-math> </named-content>); Monitoring; Near infrared radiation; Occultation; Physics; Retrieval; retrieval algorithm; Satellites; Spectral resolution
• ISSN: 1939-1404; 2151-1535
• DOI: 10.1109/JSTARS.2024.3381651

The atmospheric infrared ultraspectral sounder (AIUS) is China's first infrared occultation spectrometer onboard the GaoFen-5 satellite. This instrument provides measurements in the near-infrared and mid-infrared spectral regions with a spectral resolution of 0.02 cm<inline-formula><tex-math notation="LaTeX">^{-1}</tex-math></inline-formula>, monitoring key greenhouse gases like methane (CH<inline-formula><tex-math notation="LaTeX">_{4}</tex-math></inline-formula>). In this study, we have developed a physics-based retrieval algorithm for accurately deriving CH<inline-formula><tex-math notation="LaTeX">_{4}</tex-math></inline-formula> mole fraction profiles from infrared absorption spectra. The retrieval algorithm is applied to the AIUS and successfully obtains CH<inline-formula><tex-math notation="LaTeX">_{4}</tex-math></inline-formula> mole fraction profiles from January to December 2019 over Antarctic. The validation results show that the retrieval algorithm has a satisfactory performance using AIUS measurements, with average relative standard deviation of the differences less than 7.2% throughout the altitude range of 10-70 km.