利用三维冰雹云模式联合三维粒子增长运行模式,对一例具有累积区的雹云进一步展开研究。结果表明:(1)累积区既是雹胚和冰雹的形成区,也是二者初期的快速增长区,但并非主要的增长区;(2)源于累积区的雹胚粒子,至少要达到毫米以上才有可能最终长成中等以上大小的冰雹,而且初始粒径越大最终产生的大冰雹的尺度越大、数目越多;(3)大冰雹增长运行轨迹呈现简单的下—上—下形式,其中初始粒径较大的粒子运行轨迹与典型超级单体有相似之处,不同的是,本文初始于累积区,而超级单体则来自"胚胎帘"。
A three-dimensional hailstorm model and a three-dimensional Lagrange hail growth model were used to do further study of a hailstorm occurring in Xunyi,Shaanxi Province,on 28 July 1997,which was found out that there existed an accumulation zone in the storm in earlier researches.The modeling results showed that:(1) embryos were formed in the accumulation zone,and the accumulation zone was also the area where embryos accreted in their early stages,however,it was not the main growth area of these embryos.(2) Only when there existed millimeter-sized embryos,can large hailstones form.Moreover,the larger the initial size of particles was,the larger the final size of the hails got and more large stones formed.(3) The trajectories of large hailstones in each experiment presented a simple down-up-down manner,and interestingly,the motion of larger embryos showed some similarity to the growth of hails in classical supercell,however,embryos of classical supercell started from a zone called "embryo curtain".