星载大气痕量气体差分吸收光谱仪定标系统中铝漫反射板实验测量研究

星载大气痕量气体差分吸收光谱仪采用太阳辐射与漫反射板组合方式进行在轨光谱定标，以天底推扫方式对地观测，拥有114°的大视场. 为保证全视场光谱定标精度，此星载仪器的在轨光谱定标系统中的铝漫反射板需具有良好的朗伯特性，以保证在仪器观测视场内能够提供均匀的光源. 在实验室中利用双向反射分布函数测量仪，采用相对测量法对研制的铝漫反射板进行了朗伯特性测量. 分析结果表明，在波长180–880 nm、观测角度-70°–+70°范围内，铝漫反射板双向反射分布函数近似成余弦分布，具有较好的朗伯特性；并采用地面模拟在轨定标方法对星载仪器进行了光谱定标，定标结果表明最大偏差值为0.022 nm，满足定标精度优于0.05 nm的要求. 通过对实验测量的分析可知，研制的铝漫反射板可选作在轨定标系统的定标板. 关键词： 在轨光谱定标系统 铝漫反射板 双向反射分布函数 星载差分吸收光谱仪器

Experimental measurement of aluminium diffuser applied to calibration system of space-borne differential optical absorption spectrometer

In a space-borne differential optical absorption spectrometer, which has a large field in nadir push-broom mode the “Sun+Diffuser” method is adopted for onboard spectral calibration. Therefore the aluminium diffuser used in the space-borne spectral calibration system is required to have a good Lambert feature to ensure the full field spectral calibration accuracy of the space-borne differential optical absorption spectrometer. And it can provide a uniform source in the observing view-field of the instrument. Using bidirectional reflectance distribution function measurement instrument, bidirectional reflectance distribution function of aluminium diffuser is measured by the relative measurement method. Experimental results show that in a wavelength range of 180–880 nm and an observing view range from -70° to +70°, the bidirectional reflectance distribution function declines from middle to both sides and approximates the cosine distribution, showing that the aluminium diffuser has a good Lambert feature. The spectral calibration of the space-borne instrument is also presented with the system: high calibration accuracy is reached by the calibration system, with the maximum deviation being 0.022 nm, which meets the requirements for the accuracy better than 0.05 nm. The aluminium diffuser measured in laboratory can be chosen for the spectral calibration system.
Keywords： space-borne spectral calibration system aluminium diffuser bidirectional reflectance distribution function space-born differential optical absorption spectrometry instrument