长三角地区城市洪涝灾害韧性时空演变及其关联性分析

Analysis on Spatio-temporal Evolution and Relevanceof Urban Flood Disaster Resilience in Yangtze River Delta

洪涝灾害是长三角地区主要自然灾害之一。开展长三角地区城市洪涝灾害韧性研究,可为加快该地区韧性城市建设、实现区域一体化高质量发展提供有力保障。运用强制确定法、熵值法和空间自相关分析,从社会、经济、基础设施和环境四个维度对2008~2018年长三角地区27个城市洪涝灾害韧性时空演变特征及其关联性进行研究。结果显示:(1)时间序列上,长三角地区城市洪涝灾害韧性水平整体呈上升趋势,城市韧性指数均值从0.2565增加到0.3542;城市间韧性指数差异程度有所增大,韧性水平处于非均衡化发展阶段。(2)空间格局上,长三角地区各城市洪涝灾害韧性水平存在明显分异,呈现“中心-外围”韧性递减的分布特征;各韧性等级城市数量结构从以上海为核心的单核分布模式向以上海-南京-苏州-杭州为核心的橄榄型分布模式演变。(3)空间关系方面,除2009年外,长三角地区城市洪涝灾害韧性指数均具有正向的空间自相关性,但全局莫兰系数偏低,空间集聚效应不明显,并且经历了“分散-集中-分散”的变化过程;城市洪涝灾害韧性指数局部空间集聚现象显著的城市数量约占20%,其中“低-低”集聚类型区持续占据主导地位,区域一体化发展有待提高。

Flooding is one of the main meteorological disasters in the Yangtze River Delta.Studies on urban flood disaster resilience can provide strong support for accelerating the construction of resilient cities and realizing highquality regional integration development in the Yangtze River Delta.Using mandatory judgment method,entropy method and spatial autocorrelation analysis,the spatio-temporal evolution characteristics and their relevance of urban flood disaster resilience in the Yangtze River Delta were analyzed by considering four aspects(i.e.society,economy,infrastructure and environment)from 2008 to 2018.The main results show that:in terms of time series,the resilience level of urban flood disaster in Yangtze River Delta showed an upward trend,and the mean value of urban resilience index increased from 0.2565 to 0.3542.The difference of resilience index among cities has increased,and the resilience level is in the stage of unbalanced development.In terms of spatial evolution pattern,the resilience level of each city in the Yangtze River Delta is obviously different,declining from center to periphery;the quantity structure of each resilience level changes from single-core distribution mode to olive-type distribution mode.Based on global spatial autocorrelation,except for 2009,the regional urban flood disaster resilience index has a positive spatial autocorrelation,but the global Moran coefficient is low,the spatial agglomeration effect is not obvious,and has experienced the change process of“dispersion-concentration-dispersion”.According to the local spatial autocorrelation,the number of cities with significant local spatial agglomeration phenomenon in urban flood disaster resilience index in the research stage accounts for about 20%,and the“low-low”type area has been dominant in the local spatial agglomeration type,and the development of regional integration needs to be improved.