Sowing Rainfall Of Convective Clouds Hail Three-dimensional Numerical Simulation

The main content of this article is to analyze and compare the effect on hail suppression and rain enhancement by seeding convective cloud with silver iodide(AgI) and liquid carbon dioxide(LC). By using the mesoscale non-static mode MM5, the mesoscale background field of a hail-producing convective weather process's occurrence and development on 23 August 2001 in Beijing was simulated and compared with the biggish scale observation data, then compare with the simulate results of 3D hail cloud classified model of Institute of Atmospheric Physics, Chinese Academy of Sciences on normal cloud to confirm the accord degree of the cloud model's simulation results and the actual cloud development process.The seeding simulate results of the 3D cloud model show that no matter the seeding agent is AgI or LC, the seeding effect in the region of maximum super-cooled water is better than that in the region of maximum updraft, and that the seeding effect by AgI is better than that by LC on both hail suppression and rain enhancement. The seeding effect in the region of maximum super-cooled water by AgI is better than that by LC on rain enhancement and hail suppression, but the seeding in the region of maximum updraft, the effect on rain enhancement by LC is better than that by AgI, and that on hail suppression, AgI is better than LC. No matter what seeding method is used, the earlier the seeding time the better the effect on hail suppression and rain enhancement, Seeding with a appropriate seeding dose, or the seeding effect is not perfect with a less or larger seeding rate.The analyses and study on particle spectrum indicate that in normal cloud evaluative with time the large-scale particle's distribution that increase first then decrease recurrence the process of the hail's form then drop from the cloud. The particle spectrum's distributions visualize a gradient variety of ice crystal, snow, graupel, hail with the reduction of height. Seeding cause the increase of the small-scale particle while the decrease of the large-scale particle, and the particle specirum excursion to the small-scale particle. The compare of the distribution of the normalcloud's particle spectrum and the M-P spectrum shows that the classified spectrum can image the distribution of the cloud particle spectrum more reasonably.