大连地区一次暖区大暴雨过程分析

Analysis of a Heavy Warm Area Rainstorm over Dalian

摘要: 采用多种资料对2013年7月1~2日发生在大连地区的一次历史上少见的区域性大暴雨过程进行了诊断分析，结果表明：(1) 这次大暴雨过程是东北冷涡、副热带高压、河套气旋和“温比亚”强热带风暴等多个系统配合的结果，降水主要发生在气旋东部，是一次暖区暴雨过程；(2) 强降水可分为两个阶段，降水分布不均匀，具有明显的中尺度特征，TBB ≤ −52℃对流云团的位置和强度对短时强降水落区有较好的指示作用；(3) 降水期间大连上空湿层深厚，水汽主要来自南海北部，“温比亚”强热带风暴登陆北上具有明显的台风远距离暴雨效应，对降水的增幅有促进作用；(4) 高空槽加深和副热带高压西伸共同作用，使西南风低空急流加强，配合地面风向辅合线的东移，使大连地区中低层辐合加强，与高空强辅散区叠置，为暴雨的形成提供了有利的动力条件；(5) 大连上空存在明显的高能舌，700 hPa以下暖平流的增强促进了低层高能中心的建立，并导致对流不稳定性的加剧，是造成强降水的重要原因。

Abstract: The rare regional heavy rainstorm process which occurred in Dalian on July 1-2 2013 was ana-lyzed by using a variety of data. The results show that: (1) The heavy rainstorm process was the interaction result of multiple systems such as northeast cold eddy, subtropical high, Hetao cyclone and strong tropical storm “Rumbia”; the rainfall occurred mainly in the east of Hetao cyclone and was a warm sector rainstorm; (2) the rainstorm can be divided into two stages; uneven precipitation showed obvious mesoscale features; the position and intensity of the mesoscale convective system with TBB ≤ −52˚C was a good indication for short-time strong precipitation area; (3) during the precipitation, the wet layer over Dalian was very thick; water vapor mainly came from the north of the south China sea; the landing and northward moving of “Rumbia” had obvious effect of distant influence of tropical cyclone and contributed to the increase of precipitation; (4) since the upper trough deepened and the subtropical high stretched westward, the southwest low-level jet strengthened, which caused the middle-level and low-level convergence over Dalian strengthened together with the surface convergence line moving eastward, and this provided a favorable dynamic conditions for the rainstorm with overlaying of strong upper divergence; (5) There was an obvious high energy tongue over Dalian; the enhance of warm advection under 700 hPa contributed to the establishment of the low-level high-energy center and made the convective instability intensified, which was also an important cause of the rainstorm.