Oriented Ice Crystals: A Single-Scattering Property Database for Applications to Lidar and Optical Phenomenon Simulations
Oriented Ice Crystals: A Single-Scattering Property Database for Applications to Lidar and Optical Phenomenon Simulations
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DOI：
10.1175/jas-d-19-0031.1
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发表时间：
2019-08
影响因子：
3.1
通讯作者：
M. Saito;P. Yang
中科院分区：
文献类型：
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作者：
M. Saito;P. Yang
一个数据库（TAMUoic 2019）的散射，吸收和偏振特性的水平取向的六边形板（HOPs）和水平取向的六边形柱（HOCs）在三个波长（355，532，和1064 nm）的辐射传输模拟和遥感实施涉及定向冰晶的应用程序。在165个离散尺寸箱中，定向冰晶的最大尺寸范围为50 ~ 10000 μm。该数据库包含94个事件方向。用物理-几何光学方法（PGOM）计算了定向冰晶的单次散射特性，对于尺寸参数大于100-150的粒子，PGOM方法与不变嵌入T矩阵方法是一致的。请注意，PGOM的精度随着尺寸参数的增加而增加。PGOM计算二维相位矩阵作为散射极角和方位角的函数，并且相位矩阵随入射方向显著变化。为了推导出实际辐射传输应用中冰云的整体光学特性，基于TAMUoic 2019数据库的使用，在定向冰晶倾斜角的概率分布上对单个HOP和HOC的光学特性进行平均。与冰云的基础上的体光学性质的激光雷达信号的模拟表明，定向冰晶的分数和倾斜角的概率分布的重要性。对定向冰晶光学现象的模拟表明，所计算的定向冰晶单次散射特性在物理上是合理的。
A database (TAMUoic2019) of the scattering, absorption, and polarization properties of horizontally oriented hexagonal plates (HOPs) and horizontally oriented hexagonal columns (HOCs) at three wavelengths (355, 532, and 1064 nm) is developed for applications to radiative transfer simulations and remote sensing implementations involving oriented ice crystals. The maximum dimension of oriented ice crystals ranges from 50 to 10 000 μm in 165 discrete size bins. The database accounts for 94 incident directions. The single-scattering properties of oriented ice crystals are computed with the physical-geometric optics method (PGOM), which is consistent with the invariant-imbedding T-matrix method for particles with size parameters larger than approximately 100–150. Note that the accuracy of PGOM increases as the size parameter increases. PGOM computes the two-dimensional phase matrix as a function of scattering polar and azimuth angles, and the phase matrix significantly varies with the incident direction. To derive the bulk optical properties of ice clouds for practical radiative transfer applications, the optical properties of individual HOPs and HOCs are averaged over the probability distribution of the tilting angle of oriented ice crystals based on the use of the TAMUoic2019 database. Simulations of lidar signals associated with ice clouds based on the bulk optical properties indicate the importance of the fraction of oriented ice crystals and the probability distribution of the tilting angle. Simulations of optical phenomena caused by oriented ice crystals demonstrate that the computed single-scattering properties of oriented ice crystals are physically rational.