Research On Urban Agglomeration Resilience Level Assessment Based On Barrel Theory

In recent years,with the continuous acceleration of urbanization and expansion of urban scale in China,urban agglomeration,as a high-level spatial organization form of urban development,has received widespread attention.Urban agglomeration is a highly urbanized and integrated urban group.Compared with the disturbance and impact of many uncertain factors such as natural disasters,climate change,environmental pollution,energy shortage and economic pressure faced by the original single city,the problems and challenges faced by the urban agglomeration are more complex.In this context,urban agglomeration resilience has gradually become a research hotspot in the academic circles.Scientific quantification of the resilience level of urban agglomeration can provide a basis for decision-making in the construction of resilient cities.However,most traditional comprehensive evaluation methods only use the idea of "averaging" to carry out traditional weighted summation,and the results often reflect the overall level of the evaluated object.Therefore,how to make the urban agglomeration resilience evaluation results more consistent with the actual situation and objective laws is crucial.Based on the connotation and characteristics of urban resilience,and the the whole life cycle of disaster occurrence,this study analyzes the impact mechanism of urban resilience,and constructs a three-stage evaluation index system of urban resilience,starting from the resistance,absorption,recovery and adaptability corresponding to the "three-stage" resilience process.On this basis,based on the barrel theory,an evaluation model for urban agglomeration resilience level is established by comprehensively using the multi barrel model,entropy method,catastrophe theory,and barrel comprehensive index method.Then taking the Beijing-Tianjin-Hebei,the Yangtze River Delta,the Pearl River Delta and the Chengdu-Chongqing urban agglomerations as an example,the resilience level of the four major urban agglomerations from 2011-2020 was comprehensively analyzed,and and further in-depth analysis of the spatio-temporal evolution characteristics of the four urban agglomerations and each city was conducted using the global and local Moran’s indexes;Finally,the grey association analysis method was used to identify and analyze the key influencing factors of urban resilience.The results show that:Within the sample period,the overall resilience level of the Beijing-Tianjin-Hebei,the Yangtze River Delta,the Pearl River Delta and the Chengdu-Chongqing urban agglomerations has developed well,all reaching medium resilience or above.Among them,the resilience level of the Yangtze River Delta urban agglomeration is the highest among the four major urban agglomerations,followed by the Pearl River Delta,the Beijing-Tianjin-Hebei and the Chengdu-Chongqing urban agglomeration.In addition,the four major urban agglomeration remove the Pearl River Delta urban agglomeration,the other three urban agglomerations all have resilient short board cities,such as Hengshui,Baoding and Xingtai in the Beijing-Tianjin-Hebei urban agglomeration;Anqing,Xuancheng and Taizhou in the Yangtze River Delta urban agglomeration;Dazhou,Ziyang and Guang’an in the Chengdu-Chongqing urban agglomeration.In the future,the resilience construction and development of urban agglomerations need to focus on these cities.The resilience grade structure of the four major urban agglomerations is also different.Among them,the resilience level of cities in the Beijing-Tianjin-Hebei urban agglomeration presents a typical dual-core structure,driven by the impact of Beijing and Tianjin on Hebei Province;The resilience level of cities in the Yangtze River Delta urban agglomeration presents an olive structure of "large in the middle and small at both ends";The resilience level of cities in the Pearl River Delta urban agglomeration presents a hierarchical pyramid structure;While the Chengdu-Chongqing urban agglomeration presents a diamond structure.In addition,there are certain spatial clustering characteristics in the four urban agglomerations,such as Shijiazhuang,Hangzhou,and Chongqing,which were high-low cities for three consecutive years in2011,2016,and 2020;Chengde and Zhongshan have been low-high cities for three consecutive years.The grey correlation degree values between the three-dimensional capabilities and urban resilience level varies greatly,reflecting the disharmony and mismatch between the development of the Beijing-Tianjin-Hebei region,the Yangtze River Delta,the Pearl River Delta and the Chengdu-Chongqing urban agglomerations from 2011 to 2020.Among them,the key influencing factors include the green coverage rate of the built-up area,the per capita GDP,the number of college students per 10000 people,the density of the drainage pipes in the built-up area;the number of health technicians per 10000people;the per capita disposable income of urban residents,the per capita park green area.In the future,the improvement of the resilience level of the four major urban agglomerations can focus on the key influencing factors of resilient short board cities,so as to effectively enhance the resilience of the urban agglomerations and achieve high-quality,sustainable development of the cities,coordinated development of the urban agglomerations.