近40年大尺度气候因子对中国洪涝灾害的可能影响

基于中国1980—2018年0.5°×0.5°逐日降水数据、紧急灾害数据库数据（EM-DAT），分析了厄尔尼诺-南方涛动（ENSO）和北大西洋涛动（NAO）对中国极端降水频次及强度、洪水发生率及损失的可能影响．结论如下:1)当冬季厄尔尼诺发生后，次年我国东部沿海及黄河、长江下游地区秋季极端降水强度增加26%；当冬季拉尼娜发生后，次年我国东部地区春、夏季极端降水强度分别增加8.8%、5.1%．2)当NAO为正位相时，我国大部分地区春、夏、秋季极端降水频次较高，华东地区夏季极端降水强度增加8.5%．3)与正常年份相比，冬季厄尔尼诺或拉尼娜发生后，次年我国春季洪水损失偏多14.5%，秋季洪水发生率偏低30%；NAO为正位相时，我国春季洪水损失偏少20%，秋季洪水发生率偏高14%．4)当拉尼娜发生后及NAO正位相、负位相时，我国长江、黄河和珠江流域极端降水与洪涝灾害的变化具有一致性． 

Impact of large-scale climate factors on flood disasters in China in the past 40 years

Based on 0.5°×0.5° daily precipitation data and EM-DAT data across China from 1980–2018, this paper analyzed the impact of El Ni?o Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO) on the frequency and intensity of extreme precipitation, flood occurrence and flood damage. The findings indicate that when El Ni?o occurs in winter, the intensity of extreme precipitation in autumn in the eastern coastal areas of China, and the lower reaches areas of the Yellow and the Yangtze Rivers, will increase by 26% in the following year. When La Ni?a occurs in winter, the intensity of extreme precipitations in spring and summer in eastern China will increase by 8.8% and 5.1% respectively in the following year. When NAO is in a positive phase, the frequency of extreme precipitations in spring, summer and autumn is relatively high in most areas of China, and the intensity of summer extreme precipitations in East China increases by 8.5%. Compared with normal years, after the occurrence of El Ni?o or La Ni?a in winter, the flood damage increases by 14.5% in spring, while the flood occurrence decreases by 30% in autumn in the following year. When NAO is in a positive phase, the flood damage is reduced by 20% in the spring, while the flood occurrence increases by 14% in autumn. After the occurrence of La Ni?a and the positive and negative phases of NAO, the changes in extreme precipitations and flood disasters in the Yangtze, Yellow and Pearl River basins of China are consistent．