Emergy-based analysis of urban compound ecosystem in Urmuqi

Emergy theory brings about a quantitative method for compound ecosystem and it has being of great significance in evaluating sustainability about city.Applying the emergy analytical method,the variation of emergy structures from 1990 to 2009 of Urmuqi,as a urban compound eco-system was analyzed.Local emergy analysis was based on important emergy indicators such as purchased emergy used,self-supporting rate of emergy,emergy use per capita and so on.The results turned out that during almost 20 years,owning to local high self-supporting rate of emergy,external resources took smaller parts in urban development.Resident's life and economic growth continuously improved.With the local nonrenewable resources exploitation,population expansion,this will result in the decrease of resources,so the environmental capacity would be becoming lower.The sustainability of Urmuqi progress was discussed.Finally some reasonable proposals for Urmuqi were offered in this paper.