实测数据参数拟合的红外大气透过率仿真

Simulation of infrared atmospheric transmittance based on measured data and parameter fitting

计算红外大气透过率的常规方法主要有经验公式法和专业软件计算法,前者存在较大的误差,后者的计算过程复杂且对红外仿真系统的移植和兼容困难,因此,本文基于具体地区多年实测大气数据,利用分子的单线吸收法计算不同温度下的水蒸气和二氧化碳的吸收系数;然后,对不同高度分布的温度、压强以及气溶胶后向散射系数的解析式进行分月拟合。在此基础上,实现红外辐射大气透过率的仿真建模。仿真结果与主流专业软件MODTRAN自定义模式下的精确计算结果很接近,而且本方法使用简单、移植性强,在工程应用上具有一定的参考价值。

There are two conventional methods to calculate infrared atmospheric transmittance,including empirical for-mula method and professional software calculating method.However,empirical formula method has large errors;profes-sional software calculating method has a complicated computational process and is difficult to apply to other infrared simulation system.Therefore,based on many years of measured atmospheric data in some areas,absorption coefficients of water vapor and carbon dioxide under different temperatures were calculated by single line absorption meth-od.Analysis formulas of temperatures,pressures and backscattering coefficients which distribute in different heights were fitted according to different months.Then,the simulation calculation model of infrared radiation atmospheric transmittance was built.The simulation results are close to the calculated results by user-defined model of MODT-RAN.The method is easy and convenient to use and has certain reference value in application.