中文摘要：

非球形气溶胶的散射特性是影响辐射传输模拟准确性的重要因素.为实现非球形、非均质气溶胶散射特性的模拟，基于MRTD（multi-resolution time-domain）方法建立了一个新的气溶胶散射模型.采用MRTD技术实现了近场电磁场的计算；考虑气溶胶的特殊性，推导了基于体积积分方法的近远场外推方法，实现了粒子散射振幅矩阵和穆勒矩阵的仿真；构建了粒子吸收和消光截面的计算模型，实现了粒子积分散射特性的高精度模拟.将MRTD散射模型的结果与Mie理论、T矩阵法进行了对比，验证了模型的准确性；讨论了空间网格粗细对模拟精度的影响，并定量分析了模型的运行效率.结果表明，MRTD散射模型的相函数模拟误差小于8%，其中前向散射方向小于4%；当粒径与入射光波长相当时，消光和散射效率因子的相对误差小于0.1%；空间网格粗细对模拟精度影响显著，当粒子尺度参数小于20时，在相同模拟精度要求下，所需网格尺寸随尺度参数呈先增大后减小的特征.

英文摘要：

Scattering process of aerosol particles plays an important role in atmospheric radiative transfer since it can modify the transmission, reflection and absorption ability of atmospheric system. Owning to the uncertainty of aerosol particles＇ scattering properties, which results from their complicated geometries and inhomogeneous compositions, there still exists a considerable uncertainty in the radiative transfer numerical simulation, and simulating the scattering properties of aerosol with irregular shapes has become a hotspot in meteorological study. To this end, a new aerosol scattering model is developed based on multi-resolution time-domain （MRTD）, by which the scattering processes of nonspherical and inhomogeneous particles can be simulated. In this model, the near electromagnetic field is calculated by MRTD technique. Considering the particularity of aerosol medium, a transformation technique from near field to far field is derived based on volume integration method, and then the scattering amplitude matrix and Müeller matrix can be calculated by the obtained far electric field as well. The models for particle extinction and absorption cross section are derived from Maxwell＇s curl equations in the frequency domain, by which the integration scattering properties can be simulated accurately. The MRTD scattering model is validated by comparing with Mie theory and T matrix method for spherical particle, ellipsoidal particle and cylindrical particle, and the influence of grid size on the simulation accuracy is analyzed subsequently. In the last part, the efficiency of the MRTD scattering model is quantitatively discussed. The simulation results show that the relative errors of scattering phase function simulated by our model are less than 8%, and the errors in forward scattering direction are much smaller, which are less than 4%. The precisions for extinction and absorption efficiency are much higher than the results from the scattering phase function, and the relative errors can reduce to 0.1% for part