The Study Of Cloud Radiation Characteristics And Seeding Agent Diffusion

For weather modification, the diffusion range and space-time evolution rules of cloud seeding agent had very close relevance of work design and seeding effect, therefore, getting to know the diffusion rules and space-time distribution of cloud seeding agent and recognize the cloud physics respond after cloud seeding were very important.This article firstly gave out diffusion range and rules of different seeding ways through building diffusion calculate project, then studied the radiance difference of water and ice cloud, offered the basics of using satellite remote-sensing to recognize cloud seeding diffusion range.The main work and conlusion of the two parts were:Cloud seeding laws:This article studied the diffusion law of different seeding ways such as antiaircraft-gun,rocket and plane,based on the analytical solution of cloud seeding agent diffused in cloud, through the diffusion calculation model of point source,line source and removing point source,farther more,examined the calculation scheme by using a flight seeding track caught by NOAA satellite in Shanxi,on April14th,2000, disccused effective cloud seeding area and the flight design which can get adequate seeded in different situation.The main conclusion we got were:When usin single antiaircraft-gun at work,the range that can be effectively catalyzed was only0.5km,when5guns worked in small interval,such as300m,at one time,the range can be1.5km and last for3minutes, raise nucleation rate will largely improve work effect.When the work of rockets and planes were calculated as line source,the width which got threshold value was about7km and6.6km,took this as the basis of multi-line seeding flight interval designing, in this way we can make sure high cloud seeding agent concentration and large range in certain area;By the result of removing single point seeding,the best flight design which can make the target area get adequate seeding was’8’form flight route,preliminary developed cloud seeding diffusion calculation software system,it can calculate the removing diffusion of plane seeding area in atmospheric wind field,offer basis and condition for effect analysis and work instruction.The radiance characteristics of water and ice cloud:Studied the differences of water and ice cloud radiance characteristics,through the research of radiation character of water cloud and ice cloud single particles,unit volume particles and a whole layer of cloud particles,studied the formation principle of cloud channel after cloud seeding from microcosmic angle. And also studied radiance and reflection function changing with wavelength of water and ice cloud in 0.4～16u m which observed by satellite, and the sensitivity of water and ice cloud for effective particle size and optical thickness of1.6u m channel and1.3μm channel.The main conclusions were:For single particles,because of the difference of water and ice cloud in refractive index,the extinction coefficient,single-scattering albedo,asymmetry factor of water and ice had very big difference,the scatter character of different shape of crystal had even bigger difference with spherical crystal.The scatter characters differences between unit volumn of crystal and water particles were less because of the smooth effect of integration. The difference of radiance between water cloud and ice cloud was not very obvious,it was because in the whole level of cloud,after the smooth effect of many times of scatter,the characteristics of radiance field is not very clear.The changing trend of water and ice cloud in1.6u m channel was in contrary.but the same in1.3μm channel.