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气象:2014,40(6):723-732
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福建前汛期持续性强降水的大气低频特征分析
(1.福建省莆田市气象局,莆田 351100;2.福建省气候中心,福州 350001)
Analysis on Atmospheric Low Frequency Features of Persistent Heavy Rains During Pre Flood Season in Fujian
(1.Putian Meteorological Office of Fujian, Putian 351100;2.Fujian Climate Centre, Fuzhou 350001)
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投稿时间:2013-09-03    修订日期:2014-04-02
中文摘要: 本文采用福建1979—2010年66个气象站逐日降水资料和NCEP再分析资料和OLR资料,揭示了福建前汛期降水的低频特征,分析了福建前汛期持续性强降水同期的大气低频特征以及前期低频信号的演变特征,结果表明:(1)福建前汛期降水存在显著的低频周期,出现频率较高的前三个低频周期分别为:10~20、30~60和20~30 d;约63%的年份出现两种以上显著的低频周期;10~90 d低频变化占前汛期降水总方差的20%~30%;(2)前汛期总雨量与降水低频信号的强度呈显著正相关关系,持续性强降水的强度和持续时间与降水的低频特征关系密切,以BWO(ISO)为主的年份,持续性强降水的持续时间较短(长)。(3)福建前汛期持续性强降水期间日本以东、索马里以东和南海三个关键区皆为低频反气旋,日本至渤海湾南下的冷空气与索马里越赤道气流、南海南部越赤道气流在福建上空持续相遇形成低频气旋,导致福建上空低层低频辐合、高层低频辐散,对流活跃。(4)福建前汛期持续性强降水与热带及副热带大气低频变化密切相关,热带MJO的东传以及东亚西北太平洋地区低频信号的北传对福建持续性强降水过程的延伸期预报具有一定的指示意义。
Abstract:By using the daily precipitation data of 66 stations in Fujian and NCEP reanalysis data and OLR data during 1979-2010, this paper reveals the low frequency features of precipitation during pre flood season in Fujian and analyzes the atmospheric low frequency oscillation (LFO) features during persistent heavy rain processes and the evolution characters of the previous LFO signs. The results indicate that the daily precipitation during pre flood season of Fujian has significant features of LFO. The main low frequent periods are 10-20 d, 30-60 d and 20-30 d respectively. More than two kinds of significant cycle periods are found with proportion of about 63%. The proportion of variance contribution of 10-90 d reaches 20%-30%. The correlations between the total rainfall in pre flood season and the intensity of LFO are significantly positive, and the intensity and the duration of persistent heavy rains are closely related to the features of rainfall LFO. In the years when precipitation is mainly controlled by BWO (ISO), the duration of persistent heavy rains is shorter (longer). In addition, during the persistent heavy rain weathers, there are anticyclones over the sea area to the east of Japan, the east of Somali and the South China Sea, which cause cold flows from Japan down to Bohai Bay to encounter the two cross equatorial flows from Somali and South China Sea over Fujian, and then low frequency cyclones are formed there resulting in the low frequency convergence in the lower level and divergence in the upper level and the convection enhanced. Moreover, the persistent heavy rain in Fujian is closely related to the variations of tropical and subtropical atmospheric LFO. The eastward propagation of tropical Madden Julian Oscillation (MJO) and northward propagation of East Asia Pacific ISO have denotative significance for extended range forecast.
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基金项目:公益性行业(气象)科研专项(GYHY201306032)、福建省科技计划项目重点项目(2011Y0008)和福建省气象局开放式气象科学研究基金项目(2010K05)共同资助
引用文本:
黄丽娜,高建芸,陈彩珠,池艳珍,2014.福建前汛期持续性强降水的大气低频特征分析[J].气象,40(6):723-732.
HUANG Lina,GAO Jianyun,CHEN Caizhu,CHI Yanzhen,2014.Analysis on Atmospheric Low Frequency Features of Persistent Heavy Rains During Pre Flood Season in Fujian[J].Meteor Mon,40(6):723-732.