摘要
利用1958—2000年NCEP/NCAR再分析资料和华南测站降水资料,分析了大气热源30～60 d振荡对华南6月旱涝的影响。结果表明,在涝(旱)年对流层低层,南海至日本东南面的西北太平洋(WNP)是一个异常的低频反气旋(气旋),伴随有异常的低频热汇(热源)区,华南至日本南部存在一个异常气旋(反气旋),对应于异常的低频热源(热汇)区,华南地区低层异常辐合(辐散);平均而言,旱年华南5—6月30～60 d振荡的位相演变要比涝年的偏晚约7～11天;涝年,低频热源和气旋从南海南部北传和从西太平洋暖池区西北传,以及从140°E附近WNP的西传都十分明显,它们对华南6月降水偏多有非常重要的影响。而旱年南海及邻近区域的低频热源和气旋北传较涝年偏晚,WNP上低频热源的西伸不明显。前期南海低频热源推进的迟早以及热带WNP上的低频热源是否西传对华南6月的降水有显著影响。
Based on the NCEP/NCAR reanalysis data and the observed precipitation data in the South China from 1958 to 2000,the impact of 30～60 day oscillation of atmospheric heat sources on the drought and flood events in June in the South China is discussed.During the flood（drought） events,there exists an anomalous low-frequency anti-cyclone（cyclone） at the low level of the troposphere over the South China Sea northeastward to the northwestern Pacific,accompanied with the anomalous low-frequency heat sinks（heat sources）,while there exists an anomalous low frequency cyclone（anticyclone） with anomalous heat sources（sinks） over the area from the South China to the south of Japan.On average,the phase evolution of the low frequency in drought events is 7～11 days leading that in flood events in May to June in the South China.In flood events,there are very regular propagations of the low frequency heat sources and cyclones northward from the southern South China Sea,northwestward from the warm pool of the western Pacific and westward from the northwestern Pacific around 140 °E,which have very important impact on the abundant rainfall in June in the South China.However,in drought events,the northward propagations of the low frequency heat sources and cyclones from the South China Sea and its vicinity region are rather later compared with those in flood events,and there is no obvious westward propagation of the heat sources from the northwestern Pacific.The timing of the low frequency heat source propagation has remarkable impact on the June rainfall in the South China.
出处
《热带气象学报》
CSCD
北大核心
2010年第5期555-562,共8页
Journal of Tropical Meteorology
基金
国家自然科学基金重点项目(40730951),国家自然科学基金面上项目(40605028)共同资助
关键词
气候学
统计特征
大气热源
30~60d振荡
华南
旱涝
climatology
statistical feature
atmospheric heat sources
30～60 day oscillation
flood and drought
South China
