广东致洪特大暴雨的综合分析

THE SYNTHETIC ANALYSIS OF THE VERY HEAVY RAINSTORMS IN GUANGDONG

对广东１９４９年至１９９４年发生的１２场造成较大洪涝灾害的特大暴雨进行分析，发现广东的致洪特大暴雨基本上可以分为３类，并具有不同的环流和物理量特征：西北江并发洪水的特大暴雨一般发生在前汛期，暴雨持续时间长、范围广、灾情重，暴雨期间环流稳定，锋面降雨系统完整，暴雨层结不稳定面积大；沿海诸河及小支流洪水致洪暴雨多发生在后汛期，暴雨突发性强、持续时间短、雨强大，暴雨主要是由于热带气旋的入侵而造成，只在暴雨区附近有明显的层结不稳定，对流现象非常强烈；造成东江及其它主要支流洪水的暴雨则可能是锋面雨也可能是热带气旋雨，稳定度指数及分布状况介于二者之间。

very heavy rainstorms that caused severe floods in Pearl River drainage basin from 1949 to 1994 are analyzed here, and it is found that the very heavy rainstorms in Pearl River drainage basin can be divided into three kinds,and they have different characteristics in circulation and physical quantities. Rainstorms that cause floods in Xijiang River and Beijiang River usually happen during the first flood season of the year (Apr.-Jun.). The rainstorms last long, cover large fields and make severe disasters. There are stable circulation background and complete front precipitation systems, and large stratification instability fields. Rainstorms often cause floods in coastal rivers and small tributaries always happen during the second flood season (Jul.-Sept.). They happen suddenly, last a short time but have strong rainfall intensity. They are always caused by tropical cyclones but show significant instability only in rainstorm fields. The characteristics of rainstorms causing floods in Dongjiang River or other main tributaries are like both the above two. That is, they may be connected with fronts or tropical cyclones, and the stability degrees of them are between the above two kinds.