Droplets to Drops by Turbulent Coagulation
Droplets to Drops by Turbulent Coagulation
复制标题
通过湍流凝聚将液滴变成液滴
DOI：
10.1175/jas3431.1
复制
发表时间：
2005
影响因子：
3.1
通讯作者：
A. Wexler
中科院分区：
文献类型：
--
作者：
N. Riemer;A. Wexler
摘要本研究解决了云微物理学中的两个核心问题。首先是大水滴的来源，它启动了暖雨的快速产生。二是云滴谱在谱线两端的展宽。这项研究探讨了云中湍流如何有助于缩小我们理解上的差距。与箱模式模拟，发展的云滴光谱计算使用凝结核，最近已经来自直接数值模拟。该核心包括湍流对液滴相对速度和液滴浓度局部增加的影响，即所谓的累积效应。结果表明，在典型的大气条件下，对于小于100 μm的液滴，湍流凝聚核比沉降核大几个数量级。而对于平静的空气后30-.
Abstract This study addresses two central problems in cloud microphysics. The first is the source of large droplets, which initiates the rapid production of warm rain. The second is the broadening of the cloud droplet spectrum at both tails of the spectrum. The study explores how in-cloud turbulence can help to close the gaps in our understanding. With box model simulations, the development of cloud droplet spectra is calculated using a coagulation kernel that recently has been derived from direct numerical simulations. This kernel includes both the effect of turbulence on the relative velocities of the droplets and on the local increases in droplet concentration, the so-called accumulation effect. Under the assumption that this kernel can be extrapolated to atmospheric Reynolds numbers, the results show that for typical atmospheric conditions, the turbulent coagulation kernel is several orders of magnitude larger than the sedimentation kernel for droplets smaller then 100 μm. While for calm air after 30-...