Abstract:Various parameters are inversed when hail occurred by using Qinhuangdao Doppler weather radar data, and the relationship between various parameters and occurrence of hailstorms is extracted with 36 hailstorm cases during 2008-2015 in the eastern Hebei Province. The study results show that the averages of maximum radar base reflectivity (MaxREF), top of the storm (TOP) and vertically integrated liquid (VIL) are 62 dBz, 9.9 km and 51.6 kg?m-2 respectively when hails occur. The average storm thickness above 0℃ level layer is 5.8 km, the average thickness between 0℃ level layer and -20℃ level layer is 3.1 km, MaxREF height of the storm is 4.6 km, and the average storm moving speed is 9 m?s-1. The radar parameters corresponding to different sizes of hailstones do not change significantly. During the occurrence of hail, sudden increase phenomenon for MaxREF between the two volume scan is 7 dBz on average, sudden increase phenomenon for TOP between the two volumn scans is 6.7 km on average and sudden increase phenomenon for VIL between the two volumn scans is 17 kg?m-2 on average. This transition occurred 39, 30 and 25 min earlier than the average time of hailstorm occurrence. Such sepcical phenonmenon could be an important criterion for hail warning. In addition, the WSR 88D hail algorithm HI is evaluated. The results show that probability of detection and false acceptance rate of the hail algorithm are relatively higher. The forecasting rate of hail by the algorithm is about 43 min on average, and the hail forecast results are larger.