Long continuous rainstorm is one of the extremely catastrophic events, and its cause and forecast are of many concerns. April to June is the main rainy season in Guangdong Province, and large scale and long continuous rainstorm can easily induce flood-causing catastrophe. Data analysis shows that long continuous rainstorm lasting for over 7 days causes serious flood disaster. Daily precipitation and rain pattern from 86 meteorological stations in Guangdong Province during 1961-2008 are investigated. The climate characteristics of the annual longest continuous rainstorm is analyzed, and the preceding field of circulation and sea surface temperature (SST) with or without long continuous rainstorm are studied using composite analysis and correlation analysis.rnThe results show that the longest period of heavy rain days in Guangdong Province mainly manifests inter-decadal stage change with weak linear increasing trend. The longest period of heavy rain days in Guangdong Province are less from the mid-1970s to the 1980s than that in the other period, and long continuous rainstorm that continues for more than 7 days occurs mostly after the year of 1990. The 500 hPa height field characteristics during long continuous rainstorm are high in the west and low in the east at high-latitudes, and high in the east and low in the west at low-latitudes. European trough deepens at mid and high-latitudes and a clear ridge occurs around Balkhash and Baikal. These results show that the meridional circulation is strong and cold air is frequently active. South branch trough is active at low-latitude and subtropical high is strong. These distributions are advantageous to meeting of cold and warm air along the coast of South China Sea and form long continuous rainstorm. SST a-nomalies (SSTA) in Nino4 region is negative, SSTA in Nino3 region is weak positive, SSTA in the Kuroshio region is clearly positive, and SSTA in West Wind Drift region is weaker negative in composite SSTA with long continuous rainstorm. The composite difference of 500 hPa geopotential height and SST in March and April between long continuous rainstorm and no long continuous rainstorm shows that they have significant distinction. It also re veals that SST fiercely evolve from March to June and SSTA in Nino3 and Nino4 regions changes from negative to positive value for long continuous rainstorm, but distributive pattern of El Nino SSTA persists from March to June for no long continuous rainstorm.%该文采用合成分析、相关分析等方法研究了影响广东省6月的最长一段暴雨日数的气候特征,并对有无长连续暴雨过程的同期及其前期环流场和海温场进行分析.结果表明:7d以上的长连续暴雨大都出现在20世纪90年代以后.长连续暴雨过程500 hPa合成平均环流场上,高纬度地区呈西高东低、低纬度地区呈东高西低分布.中高纬度地区欧洲槽较深,巴尔喀什湖贝加尔湖为明显的高压脊,说明经向环流较强,冷空气活动频繁.低纬度地区南支槽活跃,副热带高压较强,有利于冷暖交绥于华南沿海,形成长连续暴雨过程.根据长连续暴雨过程的海温合成平均距平图,东太平洋Ni(n)o4区海温为负距平、Ni(n)o3区为较弱正距平,黑潮海区为较明显的正距平中心,西风漂流区以较弱的负距平为主.研究还揭示了长连续暴雨过程3-6月海温场发生了较为激烈的演变,Ni(n)o3,Ni(n)o4区海温是一个由负变正的增温过程,而无连续暴雨过程3-6月海温场的演变维持为El Ni(n)o海温分布型.
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