2007年汛期淮河流域连续性大暴雨TBB场分析

TBB Features of Continuous Torrential Rain over Huaihe River Valley in Summer of 2007

利用水平分辨率0.1°×0.1°经纬度FY-2C卫星TBB网格资料、连续性强降水过程和最强降水时段的加强加密降水资料(其中,安徽临泉县迎仙站日降水破安徽省日最大降水纪录),对应分析TBB平均场分布特征及其演变特点,揭示强降水云团生消史与暴雨发展的内在联系。结果表明:TBB低值区与淮河流域强暴雨落区有明显的对应关系,TBB值减小过程与雨强增强过程比较一致,TBB梯度大值区在某地长时间维持将产生长时间强降水。源源不断的来自南海经广西沿着副高西北侧向东北方向伸展的水汽输送,与西风槽不断带来的新鲜冷空气在淮河流域相汇,对淮河流域强降水云系的生成、发展和维持起着重要作用。同时,在此阶段TBB低值区在淮河流域一带稳定少动,南北摆动幅度小,时生时伏的变化,造成淮河流域天气53年以来全线致洪暴雨重大事件。

With the TBB data from FY-2C satellite and the hourly observed precipitation data,the TBB features of torrential rain in Huaihe River valley from June 30 to July 10,2007 are studied.Based on the records of the strongest rainfall period,some synoptic and climatic characteristics are summarized.The results show that TBB can directly and quantitatively present the features of intensity and distribution of cloud system with heavy rainfall.The torrential rainfall and the lower TBB band have a good relationship,and the southwest monsoon is very strong.The transported water vapor from the South China Sea to the northeast along the northwest side of the subtropical high and Guangxi Province,and the constant flow of fresh air from westerly trough,meet in Huaihe River valley,which plays an important part in the generation,development and maintenance of the strong convective cloud cluster in Huaihe River valley.The lower TBB band along the Huaihe River valley is less dynamically stable with a small north-south swing,and the process appear to be in a cycles of development-enhancement-weakening-regeneration,which causes in a torrential rain over Huaihe River valley.