基于北京2005年5月31日雹云个例数值模拟结果， 分析了对流有效位能（CAPE）和水平风垂直切变（下称shear）等环境因素演变对对流活动的影响， 并进一步分析了强对流云与局地环境之间的相互作用。长生命史的超级单体风暴需要shear和CAPE之间相互配合， 一般用理查逊数(Ri=CAPE/shear)表示。本文给出了个例中这种配合的具体表现： 当对流有效位能达到1000 J·kg-1时， 小的垂直风切变产生一般单体对流， 对应Ri数>10， 较强切变产生超级单体强对流， 对应Ri数在1~5之间。环境影响对流形态， 同时对流对局地环境也有明显影响： 一般单体对流组成的飑线使其移动方向的局地环境shear增大， 超级单体强对流随着其发展对环境shear的消耗明显， 使得其周边几十甚至上百公里的环境shear明显减小。强对流活动区域局地环境shear的减小和CAPE的降低相配合， 使Ri数维持在1~5之间， 有利于超级单体流型的维持。

On the base of successfully simulated hailstorm case which happened on 31 May 2005, the dependence of convective storm on the environmental factors including CAPE(the convective available potential energy) and shear(vertical wind shear) and the interaction between convective storm and local environment were studed. The result shows that the shear is very importantto convective storm type for a given amount of CAPE. The long-lived supercell storm need balance between CAPE and shear. The relationship between CAPE and shear has been expressed in term of Richardson number (Ri= CAPE/shear). In the simulated “531”case, when CAPE is more than 1000 J·kg-1 small shear bring short-lived ordinary convective cell while large shear often produce long-lived supercell storm and Richardson number is more than 10 in the former and between 1~5 in the latter. The convective storm effect local surrounding distinctly. The squall-line of ordinary cell tend to increase surrounding shear in front of it while supercell storm would dissipate more and more shear on the process of development and the area influenced spread to hundreds of kilometers. The blocking of the large-scale updraft on the horizontal airflow and the mixing of evere convective activities may be reasonable interpretation for phenomenaabove. Corresponding to the decrease of CAPE, the local shear also diminishes in the regime of evere convection. As a result, the Richarson number holds between 1~5, which would benefitfor the maintenance of supercell.