红外傅里叶光谱仪在轨光谱定标算法研究

On-Orbit Spectral Calibration Algorithm of Infrared Fourier Transform Spectrometer

风云四号A星上搭载的干涉式大气垂直探测仪的核心是一台红外傅里叶光谱仪,为了提高探测仪观测资料的定量化应用水平,必须对其进行精确的在轨光谱定标。对于傅里叶光谱仪来说,光谱位置由干涉图的采样点数和参考激光频率共同决定,因此光谱定标的关键是确保参考激光频率的稳定性。本研究利用逐线积分辐射传输模式得到参考大气吸收谱线,通过比较探测仪观测光谱与参考光谱的均方根误差来确定激光的有效采样频率,从而实现探测仪的在轨高精度光谱定标。该方法已应用于风云四号A星上搭载的干涉式大气垂直探测仪的在轨光谱定标中,具有较高的应用价值。

The geostationary interferometric infrared sounder(GIIRS) on-board FY-4 A satellite is an infrared Fourier transform spectrometer. To improve the quantitative application level of observed data, it is necessary to conduct the on-orbit spectral calibration of the GIIRS accurately. Since the spectral positions are determined by the reference laser frequency and the number of the sampling points collected from interferograms for the Fourier transform spectrometer, the key of the spectral calibration is to ensure the stability of the reference laser frequency. In this study, a line-by-line radiative transfer model(LBLRTM) is used to calculate the reference atmospheric absorption spectra. The effective sampling frequency of the laser is determined empirically by comparing the root-mean-square error between the observed and the reference spectra of the detector, achieving the on-orbit high-precision spectral calibration of the detector. This method is used for the on-orbit spectral calibration of the GIIRS on-board FY-4 A satellite, clearly demonstrating its application value.