Analysis of the Atmospheric Circulation in Relation to Persistent Rain Storm on the Meiyu Front
持续性梅雨锋暴雨的环流特征分析

This study examines the features about the large-scale circulation and the major systems during the period of the Meiyu rainstorms around middle and low reaches of the Yangtze River in 1999. The features of the persistent rainstorms are considered under a distinctive behavior of the atmospheric circulation as follows: (1) The westward staying and eastward movements of the subtropical high are directly associated with the activities of the synoptic systems around middle latitudes and the strength of the water vapor flux. (2) The development of the ridge around the North china plays a important role in keeping the Meiyu front steady. (3) The vortexes originated from the south of the Tibetan Plateau moves eastward and becomes very strong when arriving over the Yangtze River, which results in a heavy flood on the Meiyu front.