Coupling analysis of ecological environment evaluation and urbanization using projection pursuit model in Xi'an, China

Abstract

With rapid urbanization, more people are migrating to cities, making it an inevitable trend. However, urbanization has significant impacts on the ecological environment. To address this, a sustainable development model is crucial to harmonize urbanization with the ecological environment. Previous studies have focused on selecting assessment indicators, but often overlooked the objective evaluation of component weights. In this study, we developed an assessment model and index system for the urban ecological environment, considering climate, vegetation, air pollution, human activities, and disaster-prone environments based on ecological evaluation theory. The projection pursuit (PP) model was employed to integrate these indicators simultaneously. Using night light data, we evaluated the coordination between the quality of the ecological environment and the current urbanization status of Xi'an, providing recommendations for the city's sustainable development The findings indicate that: 1) The overall ecological environment of Xi'an has shown improvement over time. There has been a noticeable north–south extension of human activity. To protect the urban ecology, it is crucial to establish the Qinling-Lishan Mountain ecological corridor as a significant barrier. This corridor will play a vital role in maintaining and enhancing the ecological balance in the region. 2) Comprehensive Night Light Index of Xi'an increased significantly during the four-year period, indicating accelerated urbanization. The city's expansion towards the west and north will be accelerated, eventually connecting with Xianyang and forming a larger Xi-Xian metropolitan circle. 3) We analyzed the coordinated growth pattern between the city and ecology in Xi'an and provided suggestions for urban ecological environment governance. These findings offer a decision-making framework for future sustainable development.