Structures And Artificial Precipitation Enhancement Potential Of Summer Cell And Multiple-cell Consolidation Convective Cloud In Fujian Province

Using "713" digitized radar, the output, development and dissipation process of 101 block convective clouds have been perfectly observed from July to September 2000 in Jianyang radar station of meteorology. 97 block convective clouds have been perfectly observed by CINRAD/SA from July to September 2001 in the same way. Based on these datas, the echo Characteristics, precipitation mechanisms, and flow field Characteristics of variable convective cloud in summer in Fujian province were analyzed. By means of surface rainfall autographic records and the datas of CINRAD/SA from July to September 2001 and 2002,a multiple regression equation is established for estimating the rainfall of different phases of convective clouds.The precipitation efficiency and Artificial Precipitation Enhancement Potential of convective cloud were analyzed also.The results indicated:1) 20.79% of precipitable convective cloud in summer are warm convective cloud and 2.97% are cold convective cloud. 76.23% of precipitable convective cloud in summer are mixing convective cloud ,they has higher top, stronger echo intensity,longer lifetime,and they development more grown-up than the pure warm convective cloud. They are main cloud type of natural precipitation as well as main object of cloud seeding.2) The echo intensity, scale, height, precipitation time of multiple-cell convective cloud all bigger than that of the convective cell. The liquid water content of multiple-cell is largest, its average value in grow to grown-up phase can reach 4.8 × 10~9kg,it is the most important precipitation cloud.3) The convergence and divergence was unobvious in initiation phase, With convective cloud developing, weak convergence appearing on low-middle layer. In grow to grown-up phase, convective stronger obviously on middle-upper layer and strong divergence on upper layer. The flow come into continuously in front of cloud,at the same time,the neonatal cells merge into main body,it result in convective cloud developing continuously. In dissipation phase, convergenceweaken obviously and divergence strengthen. The whole low-middle layer become divergence except that weak convergenc in front of convective cloud.4) The precipitation efficiency in the convective cell was obviously less than that of multiple-cell convective cloud. Artificial Precipitation Enhancement Potential of convective cloud is larger.The results provided verification for farther study the structure and precipitation mechanisms of convective cloud as well as weather modification theory and seeding method in summer in Fujian province.