广州前汛期暴雨气候特征分析

Climate Features of Torrential Rain in the First Flood Season of Guangzhou

利用广州站1951～2009年的降水资料和历史天气图资料分析广州在过去59年前汛期(4～6月)暴雨气候变化特征以及暴雨产生的天气形势分类得出以下结论:1)广州前汛期暴雨累积雨量与前汛期降水变化趋势一致,呈逐年增加趋势,前汛期暴雨贡献率呈现波动变化;2)5、6月份的暴雨占前汛期累积雨量的比例呈10年左右的周期变化,未来10年广州可能再次进入5月份暴雨高发期;3)前汛期暴雨频次约占全年暴雨频次52.1%,其小波功率谱呈现4～8年的周期振荡,且在1987～2003年最为显著;4)广州前汛期暴雨偏多的年份,冷暖气团势力相当,在华南地区交汇的机会多,广州暴雨偏多,而暴雨偏少的年份,是极圈附近冷气团过于强盛而海上暖气团过于弱或者冷气团有一定的势力,但是海上暖气团过于强盛,华南地区由单一气团控制,广州暴雨偏少。

Precipitation data of Guangzhou with the historical synoptic maps were studied, to investigate the climate fea- tures and the weather patterns for torrential rainfall （hereafter as TR） events in Guangzhou during the first flood season （April to June, hereafter as FFS） in recent 59 years. Results show that 1 ） the accumulated rainfall of TR - FFS has the same increas- ing trend with the total accumulated rainfall in FFS and the contribution of the TR - FFS shows a wave pattern ; 2 ） the propor- tion of the accumulated TR during May and June in the total accumulated rainfall of FFS, has a 10 - year periodic variation, in- dicating high probability of TR in May in the next 10 years; 3） the frequency of TR - FFS contributes 52.1% to that of the whole year TR with 4 - 8 year oscillation in wavelet power spectrum ; 4 ） TR - FFS occur when cold and warm air mass converge in Guangzhou with even intensity, and single air mass dominating south China usually leads to less TR - FFS in Guangzhou.