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为了提高沙尘暴中红外系统的精度,应用电磁波在离散随机介质中传播的多重散射理论,分析红外波在沙尘暴中传播时的后向散射增强机理,给出了沙尘暴单位体积的粒子数随能见度变化的关系式,对于可见到远红外波,研究其在不同能见度的沙尘暴中传播时的多重散射效应引起的后向散射增强。结果表明对于不同波长的波,其后向散射增强不同。沙尘暴的能见度越低,后向散射增强越显著。不同类型的沙尘暴,粒子尺度分布不同;在一定能见度时,单位体积中粒子数越多的沙尘暴,后向散射增强越大;在一定的粒子数密度时,含大粒子数越多的沙尘暴,后向散射增强越显著,尤其是波长较长波的后向散射增强更明显。即,沙尘暴的能见度越低,单位体积中的粒子数越多,包含较大粒子数目较多时,后向散射和增强就越显著,则对红外系统的影响就越严重。
In order to improve the accuracy of infrared system in dust storm, the backscattering enhancement mechanism of infrared wave propagating in sandstorm is analyzed by applying the multiple scattering theory of electromagnetic wave propagation in discrete random medium. The particle number per unit volume of sand dust storm is given with the change of visibility For the visible far-infrared wave, we study the enhancement of backscattering caused by the multiple scattering effect when it propagates in sandstorms with different visibility. The results show that the enhancement of backscattering is different for waves of different wavelengths. The lower the visibility of sandstorms, the more significant the enhancement of backscatter. Different types of sandstorms have different particle size distributions. When a certain degree of visibility is reached, sandstorms with more particles per unit volume increase the backscattering more. At a certain particle density, sandstorms with larger numbers of large particles, The more significant the scattering enhancement, especially the longer wavelength wave backscatter enhancement more pronounced. That is, the lower the visibility of sandstorms, the greater the number of particles per unit volume and the larger the number of larger particles, the more significant the backscattering and enhancement, the more serious the impact on the infrared system.