基于射线追踪技术与电磁等效原理的几何光学近似模型的设计与验证  

Design and Verification of Geometric Optical Approximation Model Based on Ray Tracing Technique and Electromagnetic Equivalence Principle

作　　者：赵嘉琦 胡帅 党蕊君 刘磊 刘西川[1] 肖瑶 Zhao Jiaqi;Hu Shuai;Dang Ruijun;Liu Lei;Liu Xichuan;Xiao Yao(College of Meteorology and Oceanography,National University of Defense Technology,Changsha 410000,Hunan,China)

机构地区：[1]国防科技大学气象海洋学院,湖南长沙410000

出　　处：《光学学报》2024年第12期18-30,共13页Acta Optica Sinica

基　　金：国家自然科学基金(62105367,42175154,42205122);湖南省自然科学基金(2020JJ4662)。

摘　　要：对于大尺度参数粒子的光散射特性,目前国内研究大多采用传统几何光学近似模型(GOM)对其进行计算,但该方法在计算尺度参数小于300的粒子时效果变差。对此,将电磁等效原理与射线追踪技术相结合,并考虑衍射以及粒子吸收的影响,自主开发了一套GOM,实现了GOM计算范围的拓展。将本文计算结果与不变嵌入T矩阵模型、物理-几何光学近似模型进行对比。结果表明,本文计算结果同其他模型的结果具有较高的一致性,本文模型可为大尺度冰晶粒子光散射计算提供有效手段。Objective Cirrus clouds and some top clouds typically contain a large number of ice crystal particles,which have a strong scattering and absorption effect for visible and infrared radiation and play an important role in the balance of the atmospheric energy budget.Understanding the radiation characteristics of cirrus clouds must start with understanding the single scattering characteristics of non-spherical ice crystals.However,due to the irregular shape of ice crystal particles such as hexagonal columns and bullet flowers,the calculation of their scattering characteristics has significant uncertainty,making them one of the most uncertain factors in radiation transfer simulation.Therefore,accurately simulating the light scattering process of ice crystals is a current research focus.At present,for ice crystal particles with small and medium-sized parameters,scattering calculation models for non-spherical particles are gradually developing,such as discrete dipole approximation(DDA),invariant imbeddi ng T-matrix(IIMT matrix),and finite-difference time-domain(FDTD)method.The DDA and FDTD models are mainly employed for particles with size parameters less than 40,and the IIMT matrix model is mainly for particles with size parameters less than 100.For large-size parameter particles,most of the traditional geometric optical approximation models are adopted in China to calculate their scattering parameters.However,this method is based on the fact that the particle size is much larger than the incident light wavelength,and the effect becomes worse during calculating particles with size parameters less than 300.Therefore,it is extremely important to independently develop the geometrical optics approximation model and expand its applicable size parameter range.In this regard,we develop an improved geometric-optical approximation model by combining the electromagnetic equivalence principle with ray tracing techniques and considering the effects of diffraction and particle absorption.Methods Firstly,a ray tracing algorithm con

关 键 词：大气光学 非球形粒子 几何光学近似 光散射 

分 类 号：P401[天文地球—大气物理学与大气环境]