带电沙尘暴中的辐射传输理论研究

Sand electrical phenomenon has been confirmed by a large number of experiments in the research of the physics of wind-blown sand, and the surface charge on sands can significantly enhance the scattering and absorption of microwave have been reported in many papers, but the existed numerical models of radiation transmission in the sand/dust storms and the Processing of Remote Sensing data under the dust environment have ignored this factor. Maybe the reason is that there is no any researches on the radiation transfer theory in the charged sand/dust storms. The project will carry out research to explore this problem. This Research project is organized as follows: A) through some field experiments obtained the sand/dust concentration, electrostatic field intensity distribution information along the altitude direction; B) Based on the electromagnetic scattering model of charged particles and the information from content (A ) in this project, found a numerical model to simulate the transmission process and to describe its rule of the radiation transfer in the charged dust storms; C) through modifing the existed atmospheric radiative transfer model to discuss the influence of the sand’s electrostatic phenomena on the Remote sensing inversion results of sandstorms and the sensing data analysis in the sand dust environment.These researches will provide a reliable theoretical basis for the use of remote sensing data and images in dust environment, media parameters inversion, and it is also very important for the improvement and development of remote sensing instruments, and for the development of new means of sandstorms remote sensing.

风沙电现象在风沙物理学研究中已被大量实验所证实，而表面带电会显著增强沙尘对电波的散射和吸收作用也被许多文献所报道，但是现有沙尘暴中辐射传输过程的数值模式及沙尘环境下遥感数据处理研究都忽略了沙粒带电这一因素。其原因可能是目前并无关于带电沙尘暴中的电磁辐射传输理论的研究。本项目将针对这一问题开展科研探索。项目研究内容安排如下：A）通过野外实验测量明确沙尘暴期间高空风沙静电场强度及其沙尘浓度分布信息；B）以项目组建立的强静电场作用下带电粒子电磁散射模型以及研究内容（A）为基础，讨论带电沙尘暴中的电磁辐射传输过程和规律；C）通过修改已有大气辐射传输模式分析风沙静电现象对沙尘暴结构遥感反演以及沙尘环境下的遥感反演结果的影响程度。项目研究成果将为沙尘背景下遥感数据和图像的分析及利用、介质参数的反演等提供可靠的理论依据，并对于改善和发展遥感仪器，发展沙尘暴遥感的新手段、新方法，也具有十分重要的意义。

风沙电现象在风沙物理学研究中已被大量实验所证实，而颗粒表面带电会显著增强沙尘颗粒对电磁波的散射和吸收作用也被许多文献所报道，但是现有大气辐射传输模型以及沙尘环境下遥感数据处理研究均未考虑颗粒带电这一因素，这必将导致相关结果的可靠性需要质疑。针对这一问题，本项目深入研究了真实环境条件下带电颗粒电磁散射特性的物理建模和数值仿真研究，重点讨论了颗粒温湿度、外部环境电场强度的影响，分析了表面电荷对颗粒光学性质产生作用的物理机制，进而讨论了颗粒系统的微波辐射特性。另外，我们首次开展了沙尘天气大气电场沿高程分布的探空实验，基于此分析了沙尘天气颗粒带电极性的空间变异特性；建立了新的颗粒起电机制模型，讨论了利用微波频段雷达对沙尘暴进行遥感监测的可行性，并联合相关单位进行了初步的野外实验，对相关理论的可靠性进行了验证。本项目成果对于提高沙尘暴结构信息遥感精度、发展新的沙尘暴监测手段具有重要现实意义。