星载大气痕量气体差分吸收光谱仪的实验室定标

In-lab calibration of space-borne differential optical absorption spectrometer

采用四通道凸面光栅成像光谱仪设计了星载大气痕量气体差分吸收光谱仪,该光谱仪用天底推扫方式探测地球地表或天空散射光信号,基于痕量气体对不同谱段光信息的"指纹"吸收和差分吸收光谱算法定量获取大气痕量气体分布。针对该光谱仪的大视场、宽谱段、高分辨率(光谱、空间)等特点,提出了相应的光谱定标和辐射定标方法,建立了定标系统,实现了对载荷的光谱定标和辐射定标,并对其定标的不确定度进行了分析。结果表明,载荷光谱定标不确定度为0.027nm,辐射定标不确定度为2.96%,满足给定的技术指标要求,为载荷的定量反演提供了保证。

A space-borne differential optical absorption spectrometer was designed on the basis of a four channel Offer imaging spectrometer with a convex grating. It could acquire high accuracy radia- tion scattered by earth surfaces or air in a nadir push-broom mode, and could quantitatively obtain the trace gas distribution based on the ＂fingerprint＂ absorption of the trace gas at different spectral infor- mation and the differential optical absorption spectrum algorithm. According to the characteristics of large field, wide wavelength range, high spatial and spectral resolution of the spectrometer, the corre- sponding methods of spectral calibration and radiometric calibration were presented, and a calibration system was built. Then the spectral and radiometric calibrations of the spectrometer were realized, and the calibration uncertainty was analyzed. Experimental results show that spectral calibration un- certainty of the instrument is 0. 027 nm and the radiation uncertainty is 2.96%. The calibration accu- racy meets the given requirements and can provide strument. a foundation for quantitatively inversion of the in-