江淮流域3次致涝大暴雨过程的对比分析

Comparative Analysis of Three Heavy Rainfall Processes in the Changjiang and Huaihe River Basin

为了掌握2011年梅汛期江淮流域强降水频发特征,揭示大暴雨天气发生发展机理,为今后暴雨预报提供有益参考。利用常规探测资料、中尺度加密站资料、雷达资料和数值模式产品资料对比分析了6月25日、7月5日和7月12日发生的3次大暴雨过程。结果表明:6月25日、7月12日强降水发生受西风带冷空气南下与低空倒槽发生相互作用,倒槽东侧的偏南气流提供充足的水汽,前者为弱冷空气与强热带风暴"米雷"外围云系结合的降水,属稳定性降水,后者为对流性降水;7月5日强降水发生于副高边缘,主要由上冷下暖的不稳定层结以及低空西南急流提供的充足的水汽供应所致。多普勒天气雷达基本反射率图可以较好地追踪强降水回波,在开展大暴雨天气联防和短时临近预警中凸现作用。

In order to grasp the frequency characteristic of heavy rainfalls in the Changjiang and Huaihe River Basin during the plum rain season in 2011, reveal the occurrence and development mechanism of rainstorm weather, to provide a useful reference for future forecast of rainstorm. The three heavy rainfall processes which occurred in June 25^th, July 5^th and July 12^th were analyzed by using the conventional observational data, mesoscale dense observational data, radar data and products of numerical model. The result showed that： the heavy rainfalls which occurred in June 25^th and July 12^th caused by the interaction of the cold air of Westterlies and low level trough, the south airflow on the eastern side of the inverted trough transmitted adequate water vapor, the front belonged to stable rainfall, which caused by the interaction of the weak cold air and the external cloud of strong tropical storm ＇ Meari＇, the later belonged to convective rainfall. The heavy rainfall in July 5＇h which occurred at the edge of the west pacific subtropical high caused by unstable stratification of the cold air in the high and warm in the low and adequent water vapor supply transmitted by low level west-south jet. Base reflectivity map of Doppler radar could trace echo of heavy rainfall well, which could play an important role in heavy rainfall weather defense and nowcasting warming.