2014年5月中旬江西地区暴雨天气过程水汽输送特征分析

摘要

Based on the NECP (1°×1°) reanalysis data,conventional observational data and GDAS data, the characteristics of water vapor transportation were analyzed for a rainstorm process in Jiangxi province during 16 -17 May 2014, and water vapor source was simulated by using backward trajectory model of Hysplit. The results showed that the moistures of this rainstorm process came from the Atlantic, the West Pacific and India Ocean. And the moisture from the Atlantic was transported via the Equatorial easterlies to the West Pacific. Some of the moistures combining the moisture from West Pacific were directly transported to the south of the Yangtze River, and the others were transmitted to the rainfall area through the area of North China. Also the moisture from India Ocean combining the moisture of Bay of Bengal and South China Sea was transported to the heavy rainfall area. The vapor convergence center was formed in the south of the Yangtze River due to different moistures, with the center value reaching 300×106 kg/s. The simulation results of Hysplit model illustrated that water vapors from different levels were similar with the results from the analysis of stream function and potential function.%利用 NCEP 1°×1°的 fnl 资料、地面观测资料和 GDAS 资料，分析了2014年5月16-17日江西地区暴雨天气过程的水汽输送特征，同时使用 Hysplit 后向轨迹模式对水汽来源进行了模拟。结果表明：此次暴雨过程的水汽主要来自大西洋、西太平洋和印度洋，其中来自大西洋的水汽经赤道东风带输送至西太平洋，与来自西太平洋的水汽汇合后一部分直接输送至江南，另一部分继续向东北方向输送至日本海域附近转向，经我国华北向南输送至江南一带；来自印度洋的水汽，经孟加拉湾和南海输送至中国江南暴雨区。来自西南、东南和东北方向的气流在我国南方上空辐合，辐合中心值高达300×106 kg/s，且辐合趋于纬向型。利用 Hysplit 模式对此次暴雨区不同高度的水汽来源及输送路径进行后向轨迹模拟，结果与利用流函数和势函数分析出的水汽输送源地和路径基本一致。