中文摘要：

利用MM5模式对2003年7月一次江淮暴雨过程进行了数值模拟,结果表明：MM5对本次暴雨落区的模拟较为成功。应用模拟结果对假相当位温、水汽通量散度、z-螺旋度及湿位涡等几个综合性物理量进行了诊断,得出的主要结论为：本次暴雨发生在高能舌的前部、能量锋区南缘和低空急流左前方三者叠加的区域;水汽通量散度比较好地反映本次暴雨的强度和落区;z-螺旋度不仅能反映降水系统,对降水系统的移动也有预报指示意义;本次暴雨过程中湿斜压性和涡度垂直分量与热力不稳定对湿位涡有同等大小的贡献。

英文摘要：

A case of rainstorm over Jianghuai Region is numerically simulated by use of the nonhydrostatic mesoscale model （MM5）. The result shows that the numerical simulation of precipitation area of this rainstorm is successful. In addition, some integrated physical parameters, including equivalent potential temperature,moisture divergence flux, moist potential vorticity and z-helicity, are calculated based on the simulated results. The results also show that：heavy rainfall occurred in the overlapped area of the foreside of high energy tongue, the south of energy front and the ieft-foreside of low-level jet. Moisture convergence flux can reflect the intensity and location of this rainfall quite well. z-helicity not only can reflect the location of rain system at this time,but also can show the movement of the rain system significantly. Moist baroclinic term associated with vertical vorticity makes equivalent contribution to moist potential vorticity comparing with thermal instability in this rainstorm case.