Set pair analysis for urban ecosystem health assessment based on emergy-vitality index.

Integrating the vitality characteristic of urban ecosystem and situation of energy and materials metabolism,the urban emergy-vitality index was constructed to comprehensively represent the urban ecosystem health status by incorporating the emergy-based indices into the framework of urban vitality index.Set pair analysis(SPA),which objectively treats and systematically measures the uncertainty level,was introduced to assess the relative health status of the urban ecosystem.Through the integrated SPA-based urban emergy-vitality assessment model and the indicator weights determined by information entropy method,the relative health status based on urban emergy-vitality index among each urban ecosystem was estimated,by choosing sixteen typical Chinese cities including Beijing,Shanghai,Wuhan,Guangzhou,etc.as study objects.The urban ecosystem health states of Xiamen,Qingdao,Hangzhou,Shanghai and Beijing were better,while those of Urumchi,Chengdu and Harbin were relatively worse.