The hail cloud evolvement,the weather background,influential system,atmospheric stratification stability and radar echo characteristic are analyzed comprehensivly.

The radar echo features of three types of hail clouds and the hail-cloud identification methods by radar echoes(such as echo type,echo parameters and synthesis indexes) are described on the basis of the outcomes and experiences accumulated from the 40-year hail suppression operation in Liaoning Province.

The index for identifing the hail clouds was obtained based on the data fitting of heights of 45dBZ radar echo and the monthly averaged heights of zero-temperature level for 231 convective clouds in 165 days from 1991 to 2003 at Baoji radar observation.

A three-dimensional hailstorm numerical model with detailed microphysical processes is used to simulate a hybrid-type hailstorm occurring in Munich,south of Germany.

In severe hailstorms,hailstones always falls accompanied with some other weather disasters such as thunder,strong wind and rainstorm.

Using the 3-D convective storm numerical model(IAP-CSM3D),dynamical effects by means of artificial updraft restraint are introduced into some regions of modeling convective clouds during a short time period at different evolution stages and different areas of a hailstorm,to study physical processes which affect the precipitation formation of hailstorm.