Abstract: Most of the American scientists are inclined to believe that the 1993 excessively heavy rainfall in USA is closely connected with EL Nino. But in this paper, by using meteorological observations and statistical results, it is proposed and certified that the main causes are the thermal influence of Sargasso Sea and the dynamical effect of the interhemispheric macro-synoptic system.

Key words: excessive heavy rainfall in USA, EL Nino, thermal influence Sargasso Sea, dynamical effect of interhemispheric macro-synoptic system

摘要： 对1993年美国特大暴雨成因问题，美国科学家一般认为：主要是厄尔尼诺(EN)影响；本文利用实测资料与统计结果以及1993年7月特殊反常现象，推断出并证实了：马尾藻海(Sargasso Sea)热力影响与半球间宏观天气系统动力作用是主要原因。

关键词: 美国1993年特大暴雨, 厄尔尼诺, 马尾藻海热力影响, 半球间宏观天气系统动力作用