Numerical simulation of the 18 June 2010 severe hail process in north Jiangsu and AgI-seeding

Combining the real data,we used a three-dimensional convective cloud model developed by IAP to simulate the 18 June 2010 severe hail process that lasted for 5 h in north Jiangsu.Results showed that the characteristics of radar echo and three times of upwelling and hail forming processes were revealed by model.The hail growth was originated from the conversion of the graupel,mainly by collision of supercooled cloud and rain water.According to a series of catalytic tests,we found that the effect of hail suppression was significant after seeding at the center of supercooled rain water when the hail on the ground just formulated or intensity of hail shooting just increased.The maximum percentage of hail suppression reached 21.1%.After seeding the amount of graupel increased and its diameter decreased,so that the amount of the hail auto-conversion by graupel reduced and the growth of hail embryo was restrained because the hail embryos produced by little graupels competed for the supercooled water.