Simulation study on the reflectance of cirrus clouds at the wavelength of 1.064μm
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摘要: 为了给激光测距、激光对大气的探测等实际工程应用提供理论依据,采用逐线积分方法计算大气分子吸收,结合离散纵标法,并耦合卷云的单次散射特性,对由实心六棱柱状冰晶粒子组成的卷云在波长为1.064μm时的散射特性和辐射特性进行了理论分析,得到了该波长上激光在卷云中传输时的反射率随入射光源的位置、观测器的位置以及卷云参量(云光学厚度、粒子尺度等)的关系。结果表明,卷云在1.064μm附近对激光的主要影响是散射,吸收在消光中占了很小的部分;其次,卷云的散射明显改变了光辐射的空间分布,散射的方向变化主要由卷云的散射相函数以及光线入射角度和观测角度决定。这一结果对实际工程应用(比如激光测距、激光对大气的探测等)是有帮助的。Abstract: In order to provide a theoretical basis for the actual application such as laser ranging and laser detection of the atmosphere,line-by-line integration was used to calculate the optical thickness of atmosphere molecular absorption.Discrete coordinate method was employed to study property of cirrus clouds at 1.064μm with the single scattering properties of cirrus clouds and the atmospheric absorption.The influence of cirrus clouds on laser transmission was analyzed by changing the incident angle,the observation location and some physical parameters of cirrus clouds.The results showed that the main effect of the cirrus clouds on laser transmission is scattering at 1.064μm and the absorption take a very small part in the extinction.The spatial distribution of the radiation is changed by scattering of the cirrus clouds significantly and the direction changes of scattering are decided by scattering phase function,observation zenith angles and scattering angle.This results are helpful to the actual application.
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