摘要： 利用中尺度模式ARPS模拟了2005年7月22日一次典型华北暴雨过程的云物理特征， 对比分析了高密度大冰雹下落末速度增大时对云和降水的发展演变、 云系宏微观结构、 垂直风场以及云系的宏观热力场的影响。结果表明， 产生这次暴雨的中尺度对流系统经历了对流云团发展、 加强及合并过程， 其高层为冰晶、 雪， 中层为霰/雹、 过冷云水， 低层主要是雨水； 霰/雹形成和融化的冷云过程对雨水的形成起重要作用。高密度大冰雹下落末速度增大时： （1）对暴雨区降水量、 云的分布、 厚度和含水量有较明显的影响； （2）可以引起云中高含水量区合并， 累积含水量减小， 含水量中心位置发生变化； （3）云系有提前进入消散阶段的趋势； （4）对云中霰/雹和雨滴的垂直分布范围及其含水量极大值影响显著， 霰/雹含水量区向下延伸约1 km， 雨滴含水量最大值高度也随之降低。同时霰/雹含水量减小， 而雨滴含水量增加； （5）上升气流的发展受到抑制， 云顶高度降低， 云中含水量减小， 伴随微物理过程的相变潜热也随之减小。
A mesoscale convective system which produces heavy rainstorm in North China on 22-24 July 2005 is selected as a research case. This heavy rainstorm process is reappeared successfully by ARPS model. On the base of analysis of cloud-precipitation characteristics, the influence of graupel/hail category by varying the value of (N0h, ρg) on development and evolvement of cloud-precipitation, macro-and micro-structures of cloud are studied. The results show that the meso-β scale convective system (MCS) locat in region between north of Henan Province and south of Hebei Province. Graupel/hail melting (cold cloud process) is the main source of rain water. Graupel/hail category has smaller influence on distribution of precititation, but has bigger influence on rainfall amount in heavy rainstorm area. Graupel/hail category almost has great influence on cloud distribution, cloud thickness in different parts of cloud and total water content of cloud. When (N0h, ρg) stand for large hail, cloud system has direction of falling into dissipation stage early. Graupel/hail category almost has no effect on the microphysical structure of cloud and vertical distribution range of most particles in cloud, but has obviously effect on vertical distribution range of graupel/hail and rain, the maximum of their water content. When (N0h, ρg) stand for large hail, the vertical distribution range of graupel/hail extends downwards, the maximum water content of graupel/hail decreases, the maximum of rain increases and the height of it falls. Graupel/hail category also has effect on updraft in cloud. When (N0h, ρg) stand for large hail, updraft is decreased, and height of cloud and water content of cloud is decreased, too. Furthermore, the development of updraft is restrained, which directly caused reduction of graupel/hail melting and water vapor condensation, and reduction of latent heat of microphysical processes.
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