The effect of raindrop clustering on collision‐induced break‐up of raindrops
The effect of raindrop clustering on collision‐induced break‐up of raindrops
复制标题
雨滴聚集对碰撞引起的雨滴破碎的影响
DOI：
10.1256/qj.03.98
复制
发表时间：
2004
影响因子：
8.9
通讯作者：
G. McFarquhar
中科院分区：
文献类型：
--
作者：
G. McFarquhar
利用雨滴对互相关函数和雨滴大小分布（rsd）的先验观测，研究了雨滴聚类对雨滴平均自由路径、雨滴碰撞平均时间和雨滴碰撞率的影响。在相同降雨率下，观测到的rsd的变化导致碰撞率的变化超过2.5倍；雨滴聚集造成的影响也会使碰撞率增加2.5倍或更多。因子2.5及其变率存在高度不确定性，因为对雨滴间隔到达时间的观测相对较少，而雨滴间隔到达时间是聚类观测的基础。聚类增加了碰撞率，因为首选区域或聚类区域的大雨滴超过了同一区域的小雨滴。RSD的形式对碰撞频率有重要影响，因为雨滴下落速度的扩散，以及大雨滴超过小雨滴的能力，高度依赖于RSD。
The impact of raindrop clustering on raindrop mean free paths, mean times between raindrop collisions, and raindrop collision rates is examined using prior observations of raindrop pair cross‐correlation functions and raindrop size distributions (RSDs). Variations in observed RSDs cause collision rates to vary by more than a factor of 2.5 for identical rain rates; effects due to raindrop clustering also increase collision rates by 2.5 times or more. High uncertainty in the factor of 2.5 and its variability exists because observations of raindrop inter arrival times, upon which observations of clustering are based, are relatively rare. Clustering increases collision rates because large raindrops in preferred or clustered regions overtake smaller drops in the same regions. The form of the RSD has a significant impact on the collision frequency because the spread in raindrop fall speeds, and hence the ability of large drops to overtake small ones, depends highly on the RSD.