The analysis of meso - scale synoptic systems indicated that the occurrence and development of the local and paroxysmal meso - scale synoptic systems led to this rainfall besides the helpful macro - scale conditions . the evolution of the meso - systems depended mainly on the topography and the macro - scale conditions , among which the topography and convective instability were thought to be the most important 同时，在大尺度上升运动区中低层存在一个条件对称不稳定建立的机制，使得在暴雨区，既存在深厚的对流不稳定机制，又存在水汽输入机制和对流不稳定的触发机制，从而形成强暴雨。
The analyses suggest that the first and second categories of rainstorms are associated commonly with the strong inertial instability in the upper troposphere , as well as respectively with symmetry and convective instabilities , and their rainfall is large ; and the third and fourth categories generally produce stable precipitation with a small rainfall , and their upper tropospheres are usually inertially stable 分析湿位涡与梅雨暴雨中的惯性不稳定、对称不稳定、对流不稳定的关系发现：第1类暴雨往往与对称不稳定有关，第2类暴雨与对流不稳定有关，且这两类暴雨高层多具有强惯性不稳定，降水相对较大；第3 、第4类暴雨是稳定性降雨，高层一般不具备惯性不稳定，雨量一般较小。
The results show that there are two centers of occurrence of llsw respectively in dong bei and jiang nan ; the regional torrential rain over the yangtze river basin is closely associated with llsw during the major periods of heavy rainfall ; the diurnal variation of the number of occurrence in the middle and low reaches of the yangtze river is the strongest in china there are some significant differences between llj and nallsw in positive season , spatial variation , diurnal variation and field of pressure . by the way , the important effect of inertial stability on heavy rainfall with both low level south - westerly jet and high level northerly strong flow is analyzed theoretically . the results show that the existence of the maximum of inertial stability in the left font of the low level jet is favor of the accumulation of the moist thermal energy , and conditional symmetric instability or convective instability can be expected in this region 另外，惯性稳定性的作用以往不受重视，本文通过对西南低空急流左前方和高空偏北大风轴右后方的惯性稳定性和对称稳定性的理论分析和实例计算，表明惯性稳定性在伴有高低空急流的暴雨中有重要意义，揭示了梅雨暴雨的一种新的高低空急流耦合机制：低空急流左前方惯性稳定度大值区的存在，有利于低层湿热能量的积累，使低层倾斜对流的不稳定发展更多期望于条件性对称不稳定或对流不稳定；高空偏北大风轴(西风急流)的存在，是其右后方(右侧)出现对称不稳定的有利条件，高空相对容易出现干对称不稳定；惯性稳定性的作用，使低层的倾斜对流更偏向于垂直方向，有利于对流发展，使高层的倾斜对流更偏向于水平方向，有利于高层辐散。
The magnitude of these variables increased approximately ten times . it helped the rapid releasing of instability energy . the interaction of high - level and low - level mesoscale system leads to the rainstorm . the vertical cross section analysis of potential temperature tells us that rainstorm take place in the warm - moist and instability area . usually locate in the very stiff moist isentropes and it can lead to the development of vortex 通过对相当位温的垂直剖面分析，可知两场暴雨的中低层都为暖湿不稳定区，暖湿不稳定区上部冷空气明显扩散，暴雨产生在暖湿对流不稳定区内，通常产生在_ e陡峭和密集区中， _ e陡峭和密集区有利于涡旋发展。
