Microphysical Property Of One Shear Precipitation And Numerical Simulation Of Seeding Effect In Jilin

In this paper, by means of airborne PMS cloud particle sounding system, a complex sounding flight was made to a shear line precipitation process in Jilin province on July 1,2004, micro-physical structure, precipitation mechanics of this precipitation process are analyzed, micro-physical structure characteristics of shear line precipitation cloud system and the physical mechanics formed by natural rainfall are optimed. The results show: this shear line rainfall system mainly consists of altostratus, nimbostatts, fractus, average cloud droplet concentration, average cloud droplet diameter are different in these three kinds of clouds;cloud water content is not well-distributed along with height, the different part of the cloud has a different cloud water content;Analysis is made on particle spectrum of three sonde , meanwhile, by means of formula N (D) =N₀Exp (-λD), make a fitting to particle spectrum, analysis is made on fitting eigenparameter N_o,λ;by means of four kinds of function separately, make fitting to particle spectrum of FSSP, 2D-C, 2D-P sonde, calculation shows: for cloud particle spectrum observed by FSSP sonde, using multi Γ function to make fitting, the effect of fitting is the best;for cloud particle spectrum observed by 2D-C sonde, using multi Γ function to make fitting, the effect of fitting is better relatively, among it, fitting is relatively worse near melt layer, further analysis is needed;for cloud particle spectrum observed by 2D-P sonde, using multi Γ function to make fitting, the effect of fitting is the best. using double Γ function to make fitting, the effect of fitting in altostratus is better, but not better in nimbostatts;the precipitation cloud system of this sonde fit the concept of interaction between seeding cloud- water supply cloud leading to rainfall mentioned by Bergeron. Based on complex analysis of cloud chart and other sonde data, ice crystal mainly occurred in the upper part of altostratus or ice crystal spreading of cirrostratus, water supply cloud is center and lower part of altostratus and nimbostatts.By means of three dimension cumulus mix cloud man-made numerical model, make a simulation to all kinds of micro physical amount change after man-made rainfall seeding and effect of seeding. The simulation results show: 1 .dynamic process of cloud was effected after spreading liquid CO₂;2. seeding liquid CO2 cause the change of all kinds of micro physical amount in clouds, therefore benefit the increase of rainfall on the ground;preliminary analysis is made on seeding effect consulting radar, surface rain amount data, the results show: radar echo enhance, rain amount enlarge.