Study of the diffraction pattern of cloud particles and the respective responses of optical array probes
Study of the diffraction pattern of cloud particles and the respective responses of optical array probes
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DOI：
10.5194/amt-12-2513-2019
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发表时间：
2019-04-26
影响因子：
3.8
通讯作者：
Duroure, Christophe
中科院分区：
文献类型：
--
作者：
de Guelis, Thibault Vaillant;Schwarzenbock, Alfons;Duroure, Christophe
光学阵列探头 (OAP) 是从二维图像中获取云和降水粒子的形状、大小和数量浓度的经典仪器手段。然而，当粒子在光学设备的物平面之外成像时，记录的二维图像会因光的衍射而变形。这种现象极大地影响了云粒子微观物理特性的反演。先前对这种效应的研究主要集中在球形液滴上。在这项研究中，我们提出了一种计算各种云粒子形状的衍射图案的理论方法，以模拟 OAP 记录的响应。为了检查该方法的有效性，使用安装在测试台上的 2D-S 探头进行了一系列实验测量。使用带有压印的非圆形不透明颗粒形状的旋转玻璃盘进行测量。
Optical array probes (OAPs) are classical instrumental means to derive shape, size, and number concentration of cloud and precipitation particles from 2-D images. However, recorded 2-D images are subject to distortion based on the diffraction of light when particles are imaged out of the object plane of the optical device. This phenomenon highly affects retrievals of microphysical properties of cloud particles. Previous studies of this effect mainly focused on spherical droplets. In this study we propose a theoretical method to compute diffraction patterns of all kinds of cloud particle shapes in order to simulate the response recorded by an OAP. To check the validity of this method, a series of experimental measurements have been performed with a 2D-S probe mounted on a test bench. Measurements are performed using spinning glass discs with imprinted non-circular opaque particle shapes.