2011年夏季广东季风槽暴雨与准双周振荡  

TORRENTIAL RAINS CAUSED BY MONSOON TROUGH IN GUANGDONG AND ITS QUASI-BIWEEKLY OSCILLATION DURING THE SUMMER OF 2011

作　　者：纪忠萍[1] 谷德军[2] 孙广凤[1] 李茵茵[1] 罗秋红[1] 李晓娟[1] 

机构地区：[1]广州中心气象台,广东广州510080 [2]中国气象局广州热带海洋气象研究所/广东省区域数值天气预报重点实验室,广东广州510080

出　　处：《热带气象学报》2014年第3期432-442,共11页Journal of Tropical Meteorology

基　　金：广东省自然科学基金(S2013010016751);全球变化研究国家重大科学研究计划(2010CB950304);中国气象局华南区域气象中心项目(GRMC2012M02);广东省科技计划重点项目(2012A030200006);国家自然科学基金(41375095;41275053);广东省科技计划项目(2011A032100006;2012A061400012)共同资助

摘　　要：采用小波分析、Lanczos时间滤波器、合成分析等方法分析了2011年夏季广东季风槽暴雨与大气低频振荡的关系。结果表明,2011年夏季降水主要存在准20 d的周期振荡,季风槽暴雨过程对应强的准双周振荡。选取与夏季降水显著相关的区域（102.5-117.5°E,20-27.5°N）平均的500 hPa高度场作为影响广东夏季降水的＂500 hPa关键区＂指数,同样选取区域（110-120°E,15-22.5°N）平均的850 hPa风场作为＂850 hPa关键区＂指数;2011年夏季500 hPa关键区与850 hPa关键区分别存在显著的准23 d、准22 d周期振荡,季风槽暴雨发生在500 hPa关键区准双周振荡的波谷、850 hPa关键区准双周振荡的波峰附近。从南海南部开始的3次低频纬向风、OLR、湿度的北传与从菲律宾以东的西太平洋向西传播的低频中心相遇,导致3次季风槽暴雨过程。利用典型个例的合成分析,对2011年6—8月广东3次季风槽暴雨的准双周振荡不同位相的大气环流场的共同演变特征进行分析,它们反映了季风槽暴雨从间歇-开始-旺盛-减弱-结束期的大气环流场演变特征,为广东季风槽暴雨的中期预报提供参考依据。The relationship between this type of precipitation and quasi-biweekly oscillations during the summer of 2011 in Guangdong is analyzed with the methods of wavelet transform, Lanczos filter and composite analysis. The results show that the summer rainfall mainly exhibits quasi-20-day periodic oscillation and the torrential rain processes correspond to strong bi-weekly oscillations. The mean 500 hPa geopotential height averaged over the region of（102.5-117.5°E, 20-27.5°N） is defined as 500 hPa key region index and the mean 850 hPa southwesterly averaged over the region of（110-120°E, 15-22.5°N） is defined as 850 hPa key region index. Both regions are significantly correlated with the summer rainfall in Guangdong. The two indexes respectively exhibit quasi-23-day and quasi-22-day periodic oscillations during the summer of 2011. The torrential rain processes caused by monsoon troughs occurred near the bottom of bi-weekly oscillation of the 500 hPa index and the peak of bi-weekly oscillation of the 850 hPa index. For three times, the northward propagation of zonal wind, OLR and specific humidity from the south of the South China Sea and westward propagation of zonal wind met with the center of low-frequency oscillations from the western Pacific east of the Philippines, and led to three heavy precipitation processes. The three torrential rain processes were analyzed for common characteristics during different phases of bi-weekly oscillation. Being intermittent, they start, climax, weaken, and end, providing reference for medium-range prediction of torrential rains caused by monsoon troughs in Guangdong.

关 键 词：天气学 准双周振荡 小波分析与合成分析 季风槽暴雨 中期预报 

分 类 号：P426.62[天文地球—大气科学及气象学]