Investigations of Warm-Cloud Precipitation Physics

点击翻译按钮获取中文摘要

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.