ENSO事件对淮河流域降水的影响

用30a的资料研究表明，ENSO事件和淮河流域降水异常之间有明显的相关性。功率谱分析显示ENSO的冷事件和暖事件有三个共同的明显周期，即18个月、26个月和47个月；淮河流域降水异常的周期成分复杂，但同样存在明显的26个月周期。对ENSO事件年份淮河流域降水异常的年内分布规律的分析结果表明：El Nino年份的春季和冬季降水明显增多，而在La Nina年份降水普遍减少，尤其以7月减少最为显著；在SO指数偏高年份，淮河流域降水明显减少，尤其是9、10、11三个月，减少量都在30％以上；而在SO指数偏低年份，春季和冬季降水增多明显。时间序列的滞后分析发现淮河流域降水异常对ENSO事件有3个月左右的响应滞后时间，对EL Nino响应的滞后时间大约4～5个月。

THE IMPACT OF ENSO EVENTS ON HUAIHE RIVER BASIN'S PRECIPITATION

Studies show that there is evident correlation between ENOS events and the abnormity of Huaihe river basin's precipitation.Through power spectrum analysis,there are three obviously common periods,18 months,26 months and 47 months,about Southern Oscillation and the abnormal sea surface temperature(SST) of the east equatorial Pacific Ocean.However,the abnormality of Huaihe River basin's precipitation is very complex,there is period of 26 months which is the same period with that of ENSO events.We found the annual distribution law about the abnormity of Huaihe river basin's precipitation in ENSO events is that:in EL Nino event,the precipitation increases in spring and winter,while in LA Nina event,the precipitation decreases,especially in July.When SOI is on the high side,the Huaihe river basin's precipitation universally and evidently decreases,especially in September,October and November,the decrement is more than 30%.While SOI on the low side,the Huaihe river basin's precipitation evidently increases.