中文摘要：

本系列工作上一篇文章利用美国Goddard中心的云分辨尺度模式,对2007年7月2—9日发生在我国江淮流域的暴雨过程开展了较成功的云尺度数值模拟,并利用地面降水以及雷达等观测资料对模拟结果进行了验证。指出,模式较好地模拟出了强降水过程的时空分布和演变特征等。在此基础上,利用地面降水诊断方程,结合上述高分辨率的强降水过程模拟资料,对这段时间的暴雨过程开展详细的地面降水过程诊断分析。结果表明,这段时间的降水可分为3次主要降水过程（A、B和C）。降水过程B的峰值发生在整层大气增温、增湿过程中,而A和C发生在降温过程中。降水过程A和B以层云降水为主,水汽辐合是降水主要来源;降水前期,一部分水汽辐合的水汽用于加湿大气;而降水末期,水汽出现辐散,降水主要由局地大气变干的水汽贡献。降水过程C中,降水后期以对流性降水为主,水汽辐合、局地大气变干均对降水有正贡献;同时,存在着明显的通过局地大气变干及水汽辐散等过程相配合,将水汽由非降水区输送到降水区,从而对降水区的降水产生影响的现象。3段降水过程初步云物理收支分析表明,相对于A和B,降水过程C的冰相云物理过程更为明显,冰相水凝物生成与转化较A、B明显增强。以液相（冰相）云物理过程为主的降水过程B（C）的降水效率最高（低）,蒸发作用最小（明显）。

英文摘要：

In the first part of our work,a torrential rain event that occurred in the Jiang-Huai valley of China from 2 to 9 July 2007 is investigated by using the Goddard Cumulus Ensemble cloud-resolving model.Through comparisons between the observations and simulation,it is found that the model reproduces well the characters of the rain process,such as temporal and spatial distributions.Based on the previous work,a detailed analysis of the torrential rain process was carried out using the modeled dada by applying the surface rain diagnostic equation.The result shows that the process can be divided into three main periods（A,B and C）.The ambient atmosphere is heated and moistened before the rain rate becomes strongest during the B period,and cools down during the A and C periods.During these periods,the stratiform rain is the main type of rain and domain-mean vapor convergence supports the surface rainfall.The local vapor gain consumes part of the vapor from the convergence in the raining prophase.The local moisture loss contributes to the surface rain rate in the raining anaphase.During the C period,the convective rain is the main rain type.The vapor convergence and local vapor loss are the main players in the convective rainfall development.At the same time,the vapor transport from non-raining areas to raining areas enforced the rainfall rate as the local moisture dries and vapor converges.The time and domain-mean cloud microphysical budget shows that the ice-water conversion process is more important in the production of rain in C than in A or B and more ice hydrometeors are produced.In A and C,in which water processes are more obvious,the cloud microphysics precipitation is more efficient than in B.