Visible and Near-Infrared Spectral Calibration of Greenhouse Gas Monitor

Abstract

The detection target of greenhouse gas monitor is the concentration distribution of global atmospheric greenhouse gases (CO2, CH4, CO, etc.). In order to achieve the spectral calibration data of the monitor, a spectral calibration device was established, including tunable laser, wavelength meter, rotating engineering scatter, and other equipment, and the spectral response of the monitor was tested by spectral calibration device. In order to obtain the ILS function of a single pixel, a tunable laser is used to scan the monochrome light. The relative spectral response curve is fitted by the Gauss function. Nearly 30 spectral response curves are merged to obtain the accurate distribution of ILS. The spectral resolution and the measurement accuracy of ILS are calculated. The spectral calibration equation is obtained by choosing 10 wavelength points in the whole spectral range and fitting with cubic polynomial. Spectral calibration results show that the spectral resolution of O2A is 0.036–0.039 nm, the measurement accuracy of ILS is better than 1%, the spectral calibration accuracy is better than 0.9 pm, and the spectral resolution of weak CO2 Absorption band is 0.061–0.068 nm, and the measurement accuracy of ILS is better than 0.8%. The accuracy of spectral calibration is better than 2.5 pm. It meets the spectral calibration requirements of greenhouse gas monitor.