关键词: 暴雨, 不同天气背景, 江苏, 梅汛期, 水汽特征量

Abstract: By using June and July daily ERA reanalysis data （0.75°×0.75°）from 2010 to 2014,observation data of rainfall at each station and precipitable water vapor （PWV）data from GPS monitoring in Jiangsu from 2010 to 2015,we examine the vapor characteristics in different weather backgrounds of flood seasons by contrastive analysis methods. Results show that vapor characteristic quantities have different functions in different weather backgrounds. Relative humidity is related to rainfall. Specific humidity and PWV can be used to determine the amount of precipitation. The judgement indexes of different rainfall levels correspond to specific humidity and PWV value given in the paper. The average amount of PWV is about 60mm when the storm rain is observed in Plum Flood Season. The value is 10mm higher than that of weak precipitation. In addition,the average amount of PWV is 30-33mm for no-rain weather. Spatial distribution of rainstorm PWV presents obvious difference in different parts of Jiangsu. Heavy rain area is found in the north of Jiangsu when PWV value is high throughout the province. The area with high PWV value is the heavy rain region when PWV value is high only in the south of Jiangsu. The rainstorm area corresponds to the area with high PWV value. Heavy rain is observed in the overlay region of high relative humidity and high moisture. The distribution type of humidity and vapor content in Jiang-Huai region in the process of heavy rain is different in the above two regions. On this basis,the structure diagrams of situation and vapor during storm rain in different parts of Jiangsu are compiled.

Key words: different weather situations, heavy rain, Jiangsu, moisture characteristics, Plum Flood Season