江苏历史时期洪涝灾害时空分布特征

以江苏历史文献记录的洪涝灾害为研究对象，分析历史时期江苏地区洪涝灾害发生的时空差异性特征，探讨影响洪涝灾害时空差异性的原因。时间尺度上，历史时期江苏地区洪涝灾害明清时期多发，集中于夏秋季节，其影响因素有长时间异常降水、风暴潮以及厄尔尼诺事件等。空间尺度上，洪涝灾害多发生于太湖平原、里下河平原及沿江地区。唐宋时期，太湖平原、沿江地区是江苏省洪涝灾害最为集中的地区，明代以降苏北平原洪涝灾害更为集中，原因应该是宋代太湖平原人口激增，涸湖造田破坏了太湖东泄水道，明清后泄洪能力得到提升，长江口的演变则使得沿江地区潮灾逐渐减少，而里下河平原因为黄河夺淮入海，导致泥沙沉降，水流不畅，成为洪涝走廊。

Spatial and Temporal Distribution of Historical Flood Disasters in Jiangsu Province

Based on the historical flood documents and records from Han dynasty to Qing dynasty, this paper studies the characteristics of frequency and spatial distribution of the historical flood in Jiangsu province, and then it discusses the influence factors which affect the frequency and distribution. The conclusions can be drawn as follows. Firstly, the flood in historical period almost happened in summer and autumn, so this paper thinks that the abnormal precipitation for a long time, tide disaster caused by tropical cyclone and El Nino events are the main reasons for flood in Jiangsu province. Secondly, the flood frequency in Ming dynasty and Qing dynasty was higher than any other times. Human activities is one of main reasons which caused the flood. Thirdly, the flood frequency in Lixiahe plain, Taihu plain and the region along the Yangtze River were higher than other areas. Because these three areas are all flatness plain that is lower than its surroundings. With the Yangzi Delta developing, the tide effect became weakened, so the flood in the region along the Yangtze River in Ming and Qing dynasty decreased. Before Yuan dynasty the Taihu plain was the area where the flood was serious but after Ming dynasty the most serious area had moved to Lixiahe plain. The reason for the change is the population in Taihu plain was exploded in Song dynasty, people changed the water area into farmland which caused the water area decreased and the flood cannot flow into the sea quickly, so the flood happened frequently. After Ming dynasty the rivers were dredged for several times, so the flood can flow efficiently. The Yellow river which carries numerous sands changed its route in 1128AD; it caused almost the sands settled down in Subei plain especial Lixiahe plain. This area became the flood corridor.