Importance of shapes and compositions of wind-blown dust particles for remote sensing at solar wavelengths
Importance of shapes and compositions of wind-blown dust particles for remote sensing at solar wavelengths
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DOI：
10.1029/2002gl014947
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发表时间：
2002-05-15
影响因子：
5.2
通讯作者：
Sokolik, IN
中科院分区：
文献类型：
--
作者：
Kalashnikova, OV;Sokolik, IN
卫星气溶胶反演的质量在很大程度上取决于气溶胶光学特性的模拟精度。矿物气溶胶的光学性质取决于粒子形态、矿物学和混合状态。在这里，我们利用最近在大气中收集的灰尘样品的显微镜数据，研究灰尘颗粒的现实形态和组成如何影响粉尘混合物的光学特性。利用这些数据重建具有代表性的成分-形状-尺寸（CSS）分布，然后应用离散偶极子近似技术计算光学性质。我们证明了锐利边缘、角型粒子的存在导致散射相函数、不对称参数、光学深度和单次散射反照率与体积等效的球体或椭圆相比的各种差异。这些差异非常大，足以影响从卫星和地面遥感观测中获得的太阳波长气溶胶光学特性。
[1] The quality of satellite aerosol retrievals depends critically upon the modeling accuracy of the aerosol optical properties. The optical properties of mineral aerosols depend on particle morphology, mineralogy, and state of mixing. Here we investigate how the realistic morphology and composition of dust particles affect the optical properties of dust mixtures by utilizing microscopy data that recently become available of dust samples collected in the atmosphere. The data were used to reconstruct the representative composition-shape-size (CSS) distributions and then the discrete dipole approximation technique was applied to calculate the optical properties. We demonstrate that the presence of sharp-edge, angular-type particles results in various differences in the scattering phase function, asymmetry parameter, optical depth and single scattering albedo compared to those of the volume-equivalent spheres or ellipses. These differences are sufficiently large as to affect the retrievals of aerosol optical properties from satellite and ground-based remote sensing observations at the solar wavelengths.