| According to the work of improving seeding agents in the "Research of Precipitation Enhancement Technology and Its Demonstration", some kinds of new seeding agents are introduced. The new catalysts such as "37" shell, Agl smoke bar, liquid COa are improved and applied in present work. In this paper, experimental equipments and process are given in detail.The results of experiments show that nucleation rates of new seeding agents have been improved. In order to verify the effects of application in weather modification, some numerical simulation of stratus in Henan Province were earned out. The model used in this paper is a three-dimension model of IAP. The nucleation rates of different seeding agents are used as the initial conditions in the model, and at the same time cloud features and modification methods are paid more attention in the model. When simulating process of liquid CO2, influence of thermodynamics to clouds is fully taken into accounted.Dynamical and microphysical processes of seeded and unseeded clouds were calculated by simulation. Distinct changing features of clouds after seeding were analyzed, then some significant conclusions are got. With the suitable seeding methods in proper time and region in clouds, precipitation is enhanced. And spacial distribution is changed, for example, position of rainfall center and intensities were significantly changed. Clouds turn thicker and radar echoes turn stronger. The cloudwater in the concerned clouds was consumed quickly after seeding. Ice-phase particles appear earlier, and their concentrations and contents increased. Microphysical processes turn more active. The main mechanism of enhancing precipitation is that much ice nuclei turn into ices, and then snow; graupel are formed more by microphysical processes. The melting of graupel makes precipitation more than that of unseeded clouds.Application results of new kinds of seeding agents can provide some bases for weather modification. |
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