在对空红外系统的多光谱探测和红外仿真中,云的干扰不可忽略,所以,对云的辐射特性的研究至关重要.在不同的波段,云的辐射特性会有很大的差异,为了研究各个不同波段云的表观辐射特性,需要计算云的光谱辐射量.在典型观测模式下建立了低云的表观光谱辐射模型,研究了对云背景辐射有贡献的各个辐射分量的计算方法.基于传统的二流近似模型获取各个参数,引入云的光谱光学厚度的经验公式,进而获得了低云在中短波段的光谱辐射特性,有效地计算出了云背景在1～5μm的中短波段内的表观光谱辐亮度数据,并且节省了计算时间.经过比较发现,该模型的计算结果与实测结果有较好的一致性,可以为云背景多光谱分析、探测及仿真提供背景数据.

The disturbance of clouds is an important factor in detection and simulation for sky, therefore, the study of cloud radiation is important. In different IR wavelengths, the properties of cloud can be much different, in order to study the apparent radiation of different wavelengths, the calculation of spectral radiation of cloud is required. An apparent radiation model for typical detection is presented in this article, and the calculations of radiation contribute to the cloud radiation is studied. The acquirement of parameters in the model is in the light of traditional two stream approximation, in additional, an experience formula of spectral optical depth is introduced, consequently, the infrared spectral radiation characteristics of low clouds in short and middle wave are gained, and apparent spectral radiation is calculated in middle and short wave ,and the calculation time is saved. Result shows that actual measurements and data from the model are consistent, hence the model is applicable as the data source in the detection and simulation in the cloudy background.