Synergistic Studies of Raindrop Shapes, Oscillations and Orientations Using 2D-Video Disdrometer, Advanced Radar and Wind Tunnel

这项研究解决了一些关键的科学问题，雨的微观结构定义为雨滴的大小，形状和方向分布在广泛的雨类型和气候。虽然已经取得了很大的进展，在理解的水滴尺寸分布的变化，并已取得了一定的成功，在使用“批量”假设的平均水滴形状和方向分布，仍然有变化的雨滴形状分布参数和振荡模式，没有完全理解。 对液滴倾斜角分布的变化性的观察甚至更少。了解这些降雨微结构特征是开发精确的基于偏振雷达的雨滴尺寸分布和降雨率反演以及电磁波衰减校正算法的关键。（亨茨维尔，AL和布里斯班，Au）和先进的雷达，包括双极化ARMOR雷达在亨茨维尔，AL;布里斯班的双波长/双极化CP 2雷达和科罗拉多州格里利附近的双极化CSU-CHILL雷达。美因茨约翰内斯古腾堡大学的世界级垂直风洞设施，德国将用于专门观察自由“漂浮”液滴随时间变化的形状和振荡模式，以及对中大型液滴在与亚毫米级液滴碰撞后随时间变化的形状进行调查。该研究的更广泛影响是：（a）更好地利用新的观测能力，这是由于国家气象局业务气象雷达网即将进行偏振测量升级，以及用于短程水文应用的“填补空白”X波段雷达;（B）引入新的成果，以改善美国许多电视台使用的雷达显示器，这些电视台正计划将其C波段系统升级为双极化，以改善恶劣天气预报，以及（c）由国家和国际无线电波传播界使用关于液滴形状和方向的结果。

This research addresses a number of key science questions related to rain microstructure defined herein as the size, shape and orientation distributions of raindrops in a wide range of rain types and climatologies. Whilst great progress has been made in the understanding of drop size distribution variability, and there has been modest success in the use of "bulk" assumptions on mean drop shapes and orientation distributions, there are still variations in the raindrop shape distribution parameters and oscillation modes that are not fully understood. There are even fewer observations of the variability of the drop canting angle distribution. Knowledge of these rain microstructure characteristics is key to developing accurate polarimetric radar-based drop-size distribution and rain rate retrievals, and for electromagnetic wave attenuation-correction algorithms.This research is observationally-driven and makes use of multiple 2D-video disdrometers in different locations (Huntsville, AL and Brisbane, AU) and advanced radars including the dual-polarized ARMOR radar in Huntsville, AL; the dual-wavelength/dual-polarized CP2 radar in Brisbane, and the dual-polarized CSU-CHILL radar near Greeley, CO. The world class vertical wind tunnel facility at the Johannes Gutenberg-Universität in Mainz, Germany will be used for specialized observation of the time varying shapes and oscillation modes of freely "floating" drops, as well as an investigation into the time varying shapes of moderate-to-large drops after coalescing collisions with sub-millimetric sized drops.The broader impacts of the study are: (a) better use of new observing capability resulting from the imminent polarimetric upgrade of the National Weather Service operational weather radar network and "gap-filler" X band radars for short range hydrological applications; (b) incorporation of new results to improve radar displays used by many TV stations in the US that are planning to upgrade their C-band systems to dual-polarization to improve severe weather forecasting, and (c) use of results on drop shapes and orientations by the national and international radiowave propagation community.