浙江省近50年持续性暴雨事件的天气气候分析

用1961-2008年的浙江省各台站的逐日降水量资料和NCEP/NCAR的逐日再分析资料对浙江省1961-2008年发生的持续性暴雨过程进行统计分析,探讨近50年来浙江省持续性暴雨的主要特征。在统计的基础上,进一步对造成浙江省大范围持续性暴雨过程的主要影响系统进行归类和研究,本文将浙江省持续性暴雨过程的影响系统分为:(1)热带低压类;(2)西风带类两大类。结果表明:(1)浙江省持续性暴雨主要集中在梅汛期和秋汛期,浙西的持续性暴雨过程多于其他地区;(2)热带低压和西风带低槽、高低空急流、副热带高压是导致浙江省持续性暴雨发生的重要天气系统。其雨带位置的分布与系统所在的位置密切相关,降水强度的分布随着影响系统的不同而变化。

The Weather and Climate Analysis of the Persistent Heavy Rainfall in Zhejiang Province in the Last 50 Years

The persistent heavy rain cases in Zhejiang province from 1961 to 2008 were analyzed and discussed by utilizing the daily precipitation data at stations in Zhejiang and NCEP/NCAR reanalysis data from 1961 to 2008.Based on the statistics and the different of 500hPa upper air synoptic situation,circulation background of the regional persistent heavy rain can be divided into two different types:(1) tropical depression,(2) westerly trough.The analyzed results indicate that:(1) the persistent heavy rainfall in Zhejiang province concentrates during meiyu and autumn flood period,and it happens more frequent in the western part of Zhejiang than any other parts;(2)the west wind trough,tropical depression,subtropical high and jet are the main motion systems that lead to the persistent heavy rainfall in Zhejiang whose location is closely correlated with the impact system.The distribution of the strength of the precipitation changes with different motion systems.