中文摘要：

利用观测资料、中尺度模式MM5和一维层状云模式,分析和研究了典型层状云系的＂催化-供给＂云结构及其分布、降水形成微物理机制;通过分析云的结构、降水机制和水分转化研究了人工增雨条件。结果表明,云系的不同部位,其垂直结构也不同,云系中有3个不同高度的含水量中心：高层冰云由冰晶和雪组成,含水量中心在300hPa高度;中层云为冰水混合层,云含水量中心在600～650hPa之间;低层云在800～900hPa之间,完全由液态水组成。这些含水量中心的高度大体上与凝结率极大值的高度对应。在锋面云系的不同部位,三层云有不同的组合。多层云是云系的主要宏观结构特征,说明＂催化-供给＂云体系是冷锋降水云系的主要降水机制。锋面云系中＂催化-供给＂云的水分转化分析表明,有29%的云水转化成降水粒子,冰粒子的撞冻增长是云水转化成降水的主要过程。约有49%的冰晶转化成雪,约有92%的雪融化成霰,约有96%的霰融化成雨水,占形成雨水总量的57%。锋面云系的部位不同,降水形成的机理也不同。远离锋区的锋后部位降水几乎完全由冷云过程形成,冰粒子主要通过凝华方式增长,撞冻增长过程很弱,降水完全由冰粒子融化形成。与锋区相比,锋前区暖云过程对雨水的贡献较大,60%的雨水是由暖云过程产生的;而锋区附近冷云过程对雨水的形成贡献较大。在云结构和降水机制研究基础上分析了云的人工增雨条件,可以用云体＂催化-供给＂云结构、降水机制、过冷水含量、冰晶浓度和云的暖区含水量以及冰面过饱和水汽量判断人工增雨催化条件。

英文摘要：

Using the observation data and numerical simulation result,the structure and its distribution and the precipitation mechanism of the ＇seeding-feeding＇ cloud for a typical stratiform cloud system are studied,the artificial enhancement precipitation conditions are studied using the analysis of cloud structure and moisture transformation.The result shows that there is different vertical structures in the different parts of cloud system.The water content centers located in three levels： The upper level（nearly 300 hPa level） is consisted of ice and snow;the middle level is mixed layer with ice and water,located in 600~650 hPa;the lower level is composed by liquid water to be between 800~900 hPa levels.These levels are corresponding to heights of maximum water vapor condensation rate.In the three different parts of cloud system,there are three different cloud combinations.The multilayer structure is a main characteristic of the cloud system and ＇seeding-feeding＇ cloud is the main precipitation mechanism. The analyses of moisture transformation show that the cloud water of 29% is transformed into the precipitation particles by the accretion process.Ice crystal of approximately 49% is converted snow and snow about 92% becomes graupel.graupel of 96% is melted into rainwater and accounts for 57 percent of total rain water. Mechanism of precipitation formation is different in the different parts of frontal cloud system.In the zone away from the front zone,the precipitation is produced mainly by the cold cloud process and the growth of ice particle is mainly by sublimation process.The precipitation is formed almost completely by ice particles melting.Comparing with the frontal zone,in the prefrontal zone,contribution of warm cloud process to rain water is larger and account for 60% of the rain water;and in the near front zone,the cold cloud process is the main in forming process of rainwater.the artificial enhancement precipitation conditions are analyzed based on the cloud structure and precipitation mechanism