康熙四十六年长三角地区旱灾与气候背景

Drought and Climatic Background in the Yangtze River Delta in the 46th Year of Kangxi Period in Qing Dynasty

康熙四十六年五至七月,长三角地区长时间没有出现降水天气,引发大范围旱灾。以县级成灾分数资料为基础,复原出本次旱灾主要分布于30°—33°N,在太湖流域形成重灾中心;再利用分辨率较高的《杨大瓢日记》,重建长三角地区四至七月逐日降水序列。通过分析,得出旱灾形成的原因是该年副高势力偏强,较早完成季节性北移,导致雨带北移速度快,梅雨期出现异常。此外,本次旱灾与太阳活动、厄尔尼诺-南方涛动现象有较强的相关性。

From June to August in the 46th year of Kangxi(1707),there was no continuous precipitation in the Yangtze River Delta,which caused a large-scale drought.Based on the quantified scores of the hazard at county level,the spread of the drought was restored.It was mainly distributed between 30°-33°N,formed a serious disaster center in the Taihu Lake Basin.The daily precipitation sequence from May to August in the Yangtze River Delta was reconstructed by using Yang Dapiao diary.Through the analysis,it is concluded that the reason for the drought is that the subtropical high pressure is stronger than usual in that year,and the its northward movement is also coming earlier,resulting in the rapid northward movement of the rain belt and the abnormality in the Meiyu period.In addition,the drought is strongly related with solar activity and ENSO events.