基于VSD模型和地理探测器的北京城市内涝脆弱性评估及驱动机制分析

VSD model and geodetector-based assessment on urban waterlogging vulnerability in Beijing and analysis of its driving mechanism

近年来,城市内涝灾害频发,脆弱性研究作为城市内涝灾害评估的热点逐渐被重视。合理评估城市内涝脆弱性,探究其背后的驱动机制是城市采取抗灾减灾手段的前提。以北京市为例,基于VSD(Vulnerability Scoping Diagram)模型框架,从水文气象、地形地貌、社会经济三方面选取指标构建城市内涝脆弱性评估体系。通过GIS采用熵值法对内涝脆弱性进行评估,运用地理探测器分析了内涝脆弱性的空间格局及驱动因子的贡献程度。结果表明:(1)北京市城市内涝脆弱性呈环层结构分布,由北京市中心区域往外,脆弱性逐渐变小;(2)脆弱性最高的区域(五级)主要位于东城、西城、朝阳和丰台等区;(3)历史内涝点主要分布在位于四级、五级为主的内涝脆弱地区;(4)城市内涝脆弱性的空间格局是多因素协同作用造成的,其中建筑密度、人口密度、路网密度、NDVI对脆弱性的空间分异性具有主导作用。

Reasonably assessing urban waterlogging vulnerability and exploring the driving mechanism behind it are the premises for city to adopt the relevant disaster resistance and mitigation measures. Taking Beijing as the study case, an assessment system of urban waterlogging is established on the basis of the VSD(Vulnerability Scoping Diagram) model framework with the indexes selected from three aspects, i.e. hydro-meteorology, topography, and socio-economics. The waterlogging vulnerability is assessed with entropy value method through GIS, while the spatial patterns and contribution degrees of the driving factors of the waterlogging vulnerability are analyzed by means of geodetector. The results show that(1) the vulnerability of urban waterlogging in Beijing is distributed in a ring-layer structure and the vulnerability gradually decreases from the central area of Beijing to the outside;(2) the areas with the highest vulnerability(Level 5) are mainly located in the districts of Dongcheng, Xicheng, Chaoyang and Fengtai;(3) the historical waterlogging points are mainly distributed in the vulnerable waterlogging areas located at the vulnerable areas of waterlogging dominated by level IV and level V;(4) the spatial pattern of urban waterlogging vulnerability is caused by the synergy of multi-factors, in which the densities of building, population, road network and NDVI play leading roles in the spatial differentiation of vulnerability.