气象2017，Vol.43Issue(1)：77-83,7.DOI:10.7519/j.issn.1000-0526.2017.01.008
湖北省夏季不同阶段强降水及其大气低频特征
Characteristics of Heavy Rain Events over Hubei Province at Different Stages of Summer and Corresponding Low-Frequency Atmospheric Features
摘要
Abstract
Anstract:By using the daily precipitation data of 68 stations in Hubei and NCEP/NCAR circulation reanal-ysis data,the characteristics of the heavy rain events and low-frequency atmospheric features between the Meiyu and midsummer periods are studied.The results indicate that the quasi-biweekly oscillation of pre-cipitation exists obviously in summer over Hubei.Compared with the rains in the midsummer period,low-frequency heavy rain events in the Meiyu period are seen more often with stronger intensities.There are significant differences of low-frequency heavy rain events between the Meiyu and midsummer period.Dur-ing Meiyu period,circulations show the distribution of north-south wave trains above the East Asia Lit-toral in the mid-level troposphere.The combined impact of strong Somali cross-equatorial flow and south-west air current around subtropical high contribute to the abudant water vapor.The saddle-type field of circulations in East Asia and transformed flow field are beneficial to the formation of mesoscale cyclonic systems.In the midsummer period,however,circulations distribute in the pattern of Eurasian wave trains in middle troposphere.In lower troposphere,water vapor comes from subtropical peripheral with the weak Somali cross-equatorial flow.The north air streams from the west of the cyclone to the west of Japan Sea and the south warm-wet air streams from the periphery of subtropical high get intersected and maintained over 30°N.Before and after the heavy rain events,there are obvious differences of the low-frequency posi-tive vorticity propagation in low troposphere.The low-frequency positive vorticity during the Meiyu period shows the characteristics of standing wave while in the midsummer,it propagates westward,southward and northward obviously.关键词
梅雨期和盛夏期/低频强降水/大气低频特征/涡度传播Key words
Meiyu and midsummer period/low-frequency heavy rain/low-frequency circulation/propaga-tion of vorticity分类
天文与地球科学引用本文复制引用
肖莺,任永建,杜良敏..湖北省夏季不同阶段强降水及其大气低频特征[J].气象,2017,43(1):77-83,7.基金项目
公益性行业（气象）科研专项（GYHY201406022）、中国气象局预测核心业务发展专项（CMAHX20160501）、湖北省气象局2015年重点科技项目（2015Z03）和湖北省气象局2015年重点科技项目（2015Y07）共同资助 （）
