The Groping Study Of Numerical Simulation Of Microphysical Characteristics And Ice Seeding In Meiyu Rainstorm Clouds In The Middle And Lower Reaches Of The China Yangtze River

In this paper,the program of the mesoscale model MM5v3 compled by CAMS particular and distinguished cloud scheme was used.T106 data was used as initialization background,combining with GMS-5 infrared satellite nephogram,Radar data and ground rainfall observation data,and highly distinguishing grid program and appropriate physical processes done. Meiyu front clouds was simulated and actual rainfall process Comparative analysis of the test on 22-23 July 2002 on the Yangtze River Basin.On the basis,the micro-analysis of the physical characteristics of the Meiyu front clouds is analysed,having simulation experiments on artificial seeding and exploring the feasibility of artificial regulation regional wall.The infrared satellite nephogram and ground rainfall observation data were analysed, and contrasting simulation.We found : in the middle and lower reach of the Yangtze River, clouds developed quickly,and the main cloud band gradually become southwest-northeast distribution. At 08 clock on the 23rd,there was a rain band along the Yangtze River which was 2000km long,and has one rainstorm center more than 95mm.Jingzhou observation stations accumulated rainfall to 148.7mm on 24-hour.We analysed simulated hydrometeor distribution, and found:Meiyu front clouds "gas-liquid-solid" three-phase clouds,had strong upward motion.There were lots of snow crystal particles and less of ice particles on upper cold cloud area;layer of super-cooled water was deep in cloud;rain water was in the middle and lower parts of clouds,was the main source of the precipitation;graupel mostly exists in the region which has a large number of super-cooled water. Most of graupel in the warm region melt into rain and strengthen surface precipitationDifferent location, dosage and time of cloud-seeding of artificial ice nuclei catalytic process simulation on the same cloud system was done, the changes of precipitation and the characteristics of micro-physical change were also analysed. We found: the rainfall performed that it firstly reduced, secondly increased, and lastly reduced if seeding at the time of the development of clouds. Continuous seeding was better than single one. The longer the seeding tine, the better the effect was. On the other hand, the rainfall performed that it firstly increased, secondly reduced, and lastly increased if seeding at the time of the newborn of clouds. The effect of reducing rain of the ice dosage of 107 was as twice as 106, and 105 was not apparent.At the process of seeding, we discovered the existence of "extraterritorial effect." Namely, the process of rainfall reducing accompanied precipitation increasing, and the process of rainfall increasing accompanied precipitation reducing. Precipitation increasing or reducing was not single occurrence.