摘要
本文利用二维冰雹云模式,给出了相应的流场,设计了一个二维冰雹增长运行模式,分别对三种流型的冰雹增长运行轨迹作了模拟研究,结果表明:1.大雹的增长运行总是沿着相对水平风速零线旋转进入主上升气流区;轨迹距零线越近,冰雹长得越大;一旦远离零线,不是吹出云外,就是向下降落。2.冰雹的增长运行轨迹沿零线的上下旋转是形成冰雹多层结构的主要原因。3.形成大雹的雹胚起始出发点是位于主上升气流区外沿水平相对风速为零的区域内。
In this paper,by using the two—dimensional hailcloud model(TDHM),a traval—growthtrajectories of large hailstones have been simulated for three hailcloud airflow patterns.The re-sults show that the large hailstone enters rotatively the main updraft core along a zero line wherethe relative velocity equals zero;the closer to the zero line the trajectory is,the larger hailstonemight grow up;once the trajectory has broken away from the effect of zeroline's attraction,thelarge hailstone will either fall down to the surface or be carried away from the cloud;the multi-layer structure of hailstone may be caused by the vertical rotation of trajectory;and the initialhail embryo is located outside the main updraft region where the relative horizontal velocity ze-ro.
