不同模态沙尘暴对太赫兹波的衰减分析

太赫兹波空间传输特性研究对于太赫兹波在空间中的应用具有重要意义.为研究太赫兹波在沙尘暴天气中的传输特性,本文根据沙尘粒子尺度的对数正态分布,应用Mie散射理论和Monte Carlo方法,分析了国内不同地域的六种干沙模态沙尘暴对1—10 THz频段太赫兹波的衰减特性,给出了消光参量和衰减率与频率的关系.结果表明,随着频率的增大,1—10 THz频段太赫兹波的衰减率呈先增加后减小的趋势,沙尘暴的模态不同,太赫兹波衰减较强的频段范围有所不同.为了分析沙粒含水量对太赫兹波传输衰减的影响,计算了不同尺寸的沙尘粒子3个效率因子与含水量的关系,发现粒子尺寸不同,含水量对消光的影响也不同;应用Monte Carlo方法计算了两种湿沙模态的沙尘暴对1—10 THz频段太赫兹波的衰减,给出了衰减率与含水量及频率的关系.结果表明,随沙粒含水量增大,沙尘暴对太赫兹波衰减较强的频段向低频方向移动,含水量小于5%时,太赫兹波衰减率随含水量增大显著增强,湿度较大的沙尘暴天气对太赫兹波的传输衰减影响更大.

Analysis of terahertz wave attenuated by sand and dust storms with different modes

The research on space transmission characteristics of terahertz wave is of great significance for the application of terahertz wave in space.In order to study the transmission characteristics of terahertz wave in sand and dust storm weather,according to the lognormal distribution of dust particle sizes,Mie scattering theory and Monte Carlo method are used to analyze the attenuation characteristics of six dry sand modes of sand and dust storm in different regions of China in a frequency band of 1–10 THz,and the relationship of the extinction parameters and attenuation rate to the frequency is given.The results show that with the increase of frequency,the attenuation rate of 1–10 THz terahertz wave first increases and then decreases.Different mode of sand and dust storm leads to different frequency range of strong attenuation of terahertz wave.In order to analyze the influence of sand dust particle moisture content on terahertz wave propagation attenuation,the relationship of three efficiency factors to water content of sand dust particles with different sizes is calculated.The results show that the influence of water content on extinction is different from that of the particle size.Monte Carlo method is used to calculate the attenuation of terahertz wave by sand and dust storm in two kinds of wet sand modes,and the relationship of the attenuation rate and water content to the frequency is given,the results are compared with those from the dry sand mode,showing that the albedo of wet sand mode is obviously lower than that of dry sand mode with the same size distribution.The absorption of wet sand particles increases with water content increasing.The extinction of wet sand and dust storm results from scattering and absorption.With the increase of water content in sand particles,the frequency band with strong attenuation of terahertz wave by wet sand and dust storm moves toward low frequency.When the water content is less than 5%,the attenuation rate of terahertz wave increases significantly with the increase of water content.Sand and dust storms with higher humidity have a greater influence on the transmission attenuation of terahertz wave.