摘要
采用小波分析、相关分析、Lanczos时间滤波器等方法分析了2008年广东强龙舟水与大气低频振荡的关系。结果表明,强龙舟水期间广东逐日降水存在显著的准7～12天周期振荡即准10天振荡,广东上空的逐日500 hPa高度场存在显著的8～13天周期振荡、南海北部平均的逐日850 hPa纬向风场存在显著的准12天周期振荡。广东前汛期降水与南海北部季风的关系最密切,其次为影响广东上空的高空槽。从中太平洋开始向西传播的准10天振荡在菲律宾东侧强对流区得到加强并继续向西传播,与从南海南部北传并加强的季风相结合,导致强季风涌的出现,从而导致强龙舟水期间的2次强降水过程。利用典型位相的合成分析,对广东强龙舟水期间2次强降水过程不同位相的大气环流场的共同演变特征进行了分析,它们可为广东强降水过程尤其是龙舟水的中期预报提供参考依据。
Guangdong suffered the most serious precipitation in the dragon-boat festival of 2008 since 1951.The relationship between a strong dragon-boat precipitation in 2008 and atmospheric low-frequency oscillation was analyzed with the methods of wavelet analysis,correlation and Lanczos filter.Results showed that the daily rainfall exhibits a significant 7 to 12-day quasi-periodic oscillation（namely quasi-10-day oscillation） during the strong dragon-boat precipitation,the daily 500 hPa height over Guangdong exhibits a significant 8 to 13-day quasi-periodic oscillation,and the daily 850 zonal wind averaged over the north of South China Sea presents a significant quasi-12-day periodic oscillation.The Guangdong rainfall during the annually first rainy season is most closely correlated with monsoon over the north of South China Sea,and less closely with an upper-level trough at 500 hPa affecting Guangdong.A strong monsoon surge induced two heavy rainfall processes during this strong dragon-boat precipitation.The monsoon surge joined with a westward-propagating quasi-10-day oscillation that originated from the central Pacific and was enhanced in a strong convective region east of the Philippines and a northward-propagating monsoon that originated from the southern South China Sea was enhanced.With composite analysis of typical phases,the common evolution characteristics of atmospheric circulation of the two heavy rainfall processes were analyzed for different phases.These features can be used as reference for medium prediction of heavy rainfall processes in Guangdong.
出处
《热带气象学报》
CSCD
北大核心
2011年第1期11-21,共11页
Journal of Tropical Meteorology
基金
中国气象局气象新技术推广预报员专项(CMATG2007Y04)
广东省科技厅项目(2006B37202004)
广东省气象局项目(2008A02)
公益性行业(气象)专项(GYHY201006018)共同资助
关键词
龙舟水
高空槽
南海北部季风
低频振荡
dragon-boat precipitation
upper-level trough at 500 hPa
monsoon over the north of South China Sea
low-frequency oscillation
