ENSO对湘西地区洪水的影响

利用中国气象局公布的日降水资料建立湘西地区5～9月2、3、5d最大降水的3种极端降水指数,发现ENSO对其后雨季湘西地区的极端降水有显著影响,其中前年7月至当年2月的相关系数都达到0.4以上,通过了0.01水平的显著性检验.而1910 ～ 1981年洪水的统计显示,极端降水与湘西暴发洪水河流的条数有着很好的相关关系,而且在时间上也有较好的对应,表明极端降水是造成湘西洪水的主要原因.进一步分析发现,Nino3区海温与极端降水及洪涝之间都存在显著正相关关系,表明在El Nino年湘西地区暴发洪水灾害的可能性更大.

Effects of ENSO on the Floods in West Hunan Province

By constructing 3 monsoon precipitation extremes using the daily precipitation data of 7 meteorological stations, it was found that these precipitation extremes are significantly influenced by the former Nino3 SST. The precipitation extremes also closely related to the number of heavy flood rivers since 1910, and the precipitation extreme and the floods events occurred coineidently. The further analysis shows there is good relation between the ENSO events and the historical floods. These analyses suggest that floods disasters are prone to happened in E1 Nino years. These good relationships suggest that the advanced information and good persistence of ENSO （sea temperature in Nino 3 region） pro- vide an indicator for forecasting floods in the West Hunan Province.