Investigations of Warm-Cloud Precipitation Physics

在没有冰期参与的情况下，热带地区是如何产生大量降雨的，这个问题引起云物理学家的兴趣已有一段时间了。1985年夏天在夏威夷进行了一次实地调查，以研究这种“暖雨”过程。1985年野外项目的一个意想不到的观测结果是，在浅层信风积云中形成了极大的雨滴（直径5毫米）。从两个角度来看，这一观察结果令人惊讶。首先，它暗示了一种比以前认为的更有效的降水过程。其次，先前的实验室和模拟研究表明，雨滴破碎过程不允许大雨滴以本数据集中观察到的大浓度存在。主要研究人员将使用这个丰富的数据集继续他们的研究。重点将放在评估从浅云产生大雨滴的云尺度环境，并研究这些云内雨滴光谱的演变。

The question of how large amounts of rain are produced in the tropics without involvement of the ice phase has intrigued cloud physicists for some time. A field investigation to study this "warm rain" process was held in Hawaii in the summer of 1985. An unexpected observation from the 1985 field program was the presence of extremely large raindrops (diameters 5 mm) which formed in shallow trade-wind cumuli. This observation is surprising from two standpoints. First of all, it implies a precipitation process which is more efficient than formerly was thought likely. Secondly, previous laboratory and modelling studies indicate that drop break-up processes would not allow large raindrops to exist in as large concentrations as observed in this data set. The Principal Investigators will continue their research using this rich data set. Special emphasis will be placed on evaluating the cloud-scale environment that produces large raindrops from shallow clouds and to study the evolution of drop spectra within these clouds.