5 August 2009 Spectral calibration of the space-borne infrared imaging Fourier transform spectrometer
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The Space-borne Infrared Imaging Fourier Transform Spectrometer (SBFTS) carried by FY-4 meteorological satellite is one of infrared remote sensing instruments. It acquires the temperature, pressure and humidity of atmosphere on geostationary orbit, and supplies the input data for numerical weather prediction. It not only can detect the spectrum of the target but also can imaging. The SBFTS carry 16×4 plane array detectors. For the proper use of the SBFTS it is imperative to provide high quality spectral characterization and characterizations of the instrument line shape (ILS). Objective: This paper's mainly analyses the off-axis factor that influence the ILS of SBFTS and convinces it through experiment. And the spectral calibration of SBFTS is according to the ILS. Methods: The accuracy of spectral-calibration of SBFTS lies on its ILS. First, the main factors that will influence the ILS are discussed here. They are the finite optical path difference and the off-axes effect because of using plane array detectors. The ILS of Fourier transform spectroscopy is influenced by the angular distribution of light in the interferometer's off-axis detector. The paper studies the effect to spectral calibration by off-axis detectors, and then makes ILS simulation for rectangular detector based on the sounder's 16×4 plane array detectors structure. The absorption line shape of CO is Lorentzian distribution in the laboratory environment. Now the ILS and the absorption line shape of the CO are given. They can be combined to the instrument detecting line shape theoretically. So the theoretical position of the absorption peak detected by the SBFTS is acquired. The frequency of absorption peak is red-shift. And the spectrum is broadened. According to the reference spectrum the spectrum calibration coefficients of each pixel is derived. And the absorption peak of CO also can be detected using the gas cell methodology. Finally the calibration coefficients are used to calibrate the spectrum of CO detected by the SBFTS. Results: The spectral-calibration coefficients of each pixel are presented and proved by the calibration experiment of CO. The relative calibration accuracy is up to 10-6.
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Peng Liu, Peng Liu, Zhanhu Wang, Zhanhu Wang, Peigang Wang, Peigang Wang, Jianwen Hua, Jianwen Hua, } "Spectral calibration of the space-borne infrared imaging Fourier transform spectrometer", Proc. SPIE 7383, International Symposium on Photoelectronic Detection and Imaging 2009: Advances in Infrared Imaging and Applications, 738311 (5 August 2009); doi: 10.1117/12.835035; https://doi.org/10.1117/12.835035

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