关键词: 局地短时暴雨, 对比分析, 露点锋, 中α尺度低压, T数值预报产品检验

Abstract: Based on the conventional observation data, precipitation data from automatic stations and NCEP reanalysis data (1°×1°) from NCEP/NCAR center, geopotential height field at 500 hPa, vertical wind velocity field, θse field and vapor flux divergence field of three local short-time heavy rains in July, 2009 were compared. The results show that the falling areas of three local heavy rains in the western and northern Liaoning province correspond with the locations of high ascending velocity centers, while those in the southeastern Liaoning province locate in the edge of high ascending velocity regions. Dew-point front, meso-α-scale low pressure and warm shear line are the direct reasons forming three local short-time heavy rains. It suggests that weak weather forcing occurs when it rains in most regions according to T639 forecast production. The superposition regions of vapor convergence, high-energy tongue and ascending velocity large value center should be considered at this time. If there is a trigger mechanism of mesoscale system in such area, it will probably be the falling area of local heavy rain.