Numerical Studies on Cloud Physics Characteristic and Influence of the Graupel/Hail Category on Cloud and Precipitation during a Heavy Rainstorm over North China

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.