Study on the formation process of warm rain using quasi-real scale artificial cloud experimental system

暖雨的开始严重依赖于直径大于50微米的云滴的存在。利用一个准真实尺度的人工云实验系统，研究了确定云滴尺寸分布的条件。影响云滴大小分布的参数有很多。通过对竖井内不同浓度气溶胶形成的云滴尺寸分布的观测，在实践中证明了在高浓度的CCN浓度下形成大量的小尺寸云滴，在低浓度的CCN浓度下形成少量的大尺寸云滴。仅对竖井底部的相对湿度和CCN光谱的差异对云滴光谱的影响进行了定量估计。人工云实验系统后来从龟川转移到龟石，但实验研究仍在继续。利用以前的凝结云滴数值模式，定量地估计了只有气溶胶的基本成分和垂直速度对云滴光谱的影响。这些结果阐明了暖雨的形成机制。

The initiation of warm rain is critically dependent on the presence of cloud droplets larger than 50mum in diameter. The conditions that determine the size distribution of cloud droplets was studied using a quasi-real scale artificial cloud experimental system. Many parameters affect the size distribution of cloud droplets. From observations of the size distribution of cloud droplets that were formed on various aerosol concentrations introduced into a vertical shaft, it was proved in practice that a large number of small-sized cloud droplets are formed in the case of a high CCN concentration and a small number of large-size cloud droplets are formed in the case of a low CCN concentration.Next, numerical simulations were carried out under the conditions that air parcels move upward in the shaft and grow into cloud droplets by condensation. The effects of only the relative humidity at the bottom of the shaft and only differences in CCN spectra on the cloud droplet spectra were quantitatively estimated.The artificial cloud experimental system was later transferred from Kamisunagawa to Kamaishi, but experimental studies were continued. Using the previous numerical model of cloud droplets formed by condensation, the effects of only the elemental components of aerosol and only the vertical velocity on the cloud droplet spectra were quantitatively estimated. The results elucidated the formation mechanism of warm rain.