沙尘暴对红外辐射的消光特性分析（特约）

基于Mie散射理论和Monte Carlo方法，分析了国内七种模态沙尘暴对0.86~20 μm波段红外辐射的消光和衰减特性。研究结果表明:对于小尺寸的沙尘粒子，在近、中波红外，消光效应主要是散射作用的结果；对于大尺寸的沙尘粒子，红外消光是吸收和散射共同作用的结果。比较了沙尘暴单次散射和多重散射产生的衰减率差异，多重散射的衰减率小于同一条件下的单次散射衰减率，差异随可见度的增大而减小，基于Monte Carlo方法计算的多重散射衰减率比消光系数更能全面反映沙尘暴对红外辐射强度衰减的影响。六种大颗粒模态沙尘暴比小颗粒模态沙尘暴的红外衰减强度大，衰减率基本随着波长的增大而增大；小颗粒模态沙尘暴的衰减率随波长的变化有明显的起伏，在7.9~12.5 μm范围内有峰值，在13~20 μm范围内衰减率对波长不敏感。

Analysis of extinction characteristics of sandstorm to infrared radiation(Invited)

The extinction and attenuation characteristics of seven modes of sandstorm in China for 0.86 -20 μm band infrared radiation were analyzed based on Mie scattering theory and Monte Carlo method. The results show that for the small size dust particles, the extinction effect is mainly the result of scattering in the near and middle infrared, and for the large size dust particles, the infrared extinction is the result of absorption and scattering. The attenuation rate difference of single scattering and multiple scattering of sandstorm are compared. The attenuation rate of multiple scattering is less than that of single scattering under the same condition, and the difference decreases with the increase of visibility. The multiple scattering attenuation rate calculated based on Monte Carlo method is more comprehensive than the extinction coefficient to reflect the influence of sandstorm on infrared radiation intensity attenuation. The infrared attenuation intensity of six kinds of large particle mode sandstorm is greater than that of small particle mode sandstorm, and the attenuation rate increases with the increase of wavelength. The attenuation rate of the small particle mode duststorm fluctuates obviously with the change of wavelength, with a peak value in the range of 7.9–12.5 μm, and is not sensitive to the wavelength in the range of 13–20 μm.