摘要
利用1961—2013年华南区域305个国家级气象台站日降水资料、1980—2013年5—6月NCEP/CFSR再分析资料（分辨率0.5×0.5）等,定义华南前汛期持续性暴雨和暴雨持续日数,分析近53 a华南前汛期持续性暴雨特征及其大尺度环流形势;归纳有利于华南前汛期持续性暴雨发生的4种典型环流类型。结果表明：（1）华南前汛期持续性暴雨过程主要集中在5—6月,并存在准20 a振荡周期;1960年代前半段6月暴雨次数多,1960年代末期到1980年代5月暴雨次数明显增加,1990年代至2013年暴雨主要出现在6月,2006年后5月暴雨次数逐渐增加;暴雨过程持续日数一般3~4 d,超过10 d以上的单次过程仅4次。（2）华南前汛期持续性暴雨分为东亚槽底型、两脊一槽型、多涡旋型和纬向型,东亚槽底型和两脊一槽型次数相对较多,主要发生在5月下旬—6月下旬;纬向型次数最少,主要在5月上旬—6月初。（3）各型持续性暴雨过程500 h Pa中高纬地区环流特征各异,其共性是均有利于北方冷空气南下影响华南,低纬地区西太平洋副热带高压（副高）和孟加拉湾南支低槽维持少动,低层850 h Pa华南盛行西南暖湿急流;持续10 d左右的暴雨过程相较持续3~5 d的暴雨过程,副高位置偏西偏强,华南上空多短波槽活动,850 h Pa西南季风气流位置偏西偏北、风速偏大。
Based on daily precipitation observations from 305 national weather stations over South China from 1961 to 2013 and NCEP/CFSR 6-hourly reanalysis data with 1°×1° resolution between May and June from 1980 to 2013, giving the definition of sustained torrential rain and torrential rain days during the pre-flood season in South China, we have analyzed the characteristics and the large scale circulation situation, and induced four typical circulation patterns of sustained torrential rain events. The results indicate that the sustained torrential rain events during the pre-flood season in South China mainly occur between May and June, and show a quasi-periodic oscillation of 20 years.Torrential rain in the first five years of the 1960 s mostly appeared in June, from the late 1960 s to 1980 s much in May, from 1990 s to 2013 mainly in June, and that in May clearly increased after 2006. Torrential rain event generally continues 3-4 days, and events lasting for more than 10 days only occurred 4 times. The circulation patterns that cause the sustained torrential rain during the pre-flood season in South China are classified into four types, i.e. East Asian trough bottom pattern, two ridges and one trough pattern, multi-vortex pattern and zonal pattern. Among those patterns, the East Asian trough bottom pattern and the two ridges and one trough pattern occur more frequently than other two patterns, with mainly between late May and late June. Meanwhile, the zonal pattern occur the least, with mainly between early May and early June. Different patterns of sustained torrential rain events present the different circulation characteristics at 500 h Pa in the middle high latitudes. They also present general characters, including being propitious to north cold air shift southward to affect South China, West Pacificsubtropical high（SH） and south branch trough over the Bay of Bengal in the low latitudes being stable, and southwest warm and wet airflow at850 h Pa dominating in South China. Compared to torrential rain events of
出处
《暴雨灾害》
2016年第2期109-118,共10页
Torrential Rain and Disasters
基金
国家自然科学基金项目(41375057
41328007)
灾害天气国家重点实验室基金项目(2014LASW-A05)
湖北省气象局科技发展基金青年项目(2016Q04)
关键词
持续性暴雨
环流分型
前汛期
华南
sustained torrential rain
circulation pattern
pre-flood season
South China
