Ecological Security Assessment And Early Warning On Rapid Urbanization Area Based On GIS And RS

The paper study on the methods of the ecological security evaluation and the ecological security early warning based on the domestic and foreign scholars and combine the GIS and RS method to the existing ecological models,then evaluate and warn the ecological security of Yiwu which is in the fast development. The mainly research content and conclusion in this article includes the following aspects:First, based on the remote sensing data and statistics data in 2000 and 2007, and take on the principle of scientific, purposive, practicably and spatial,at the same time consider the various. Then constructed four levels ecological security evaluation indicator system of Yiwu based on PSR model;Second, achieved the dynamic monitoring of the ecological security evaluation indicators with the main methods of RS and GIS and combined with the ecology, mathematical science;Third, confirmed the weight of the indicators in different levels by using the methods of analytic hierarchy process and expert consultation on the platform of MATLAB.Fourth, take on comprehensive index evaluation method and fuzzy comprehensive evaluation method realized the monitoring of the ecological security in different temporal-spatial scales. The results indicated that the evaluation of two methods with similar consistency. The pixel scale show that Yiwu's ecological security level was high and the overall ecological security pattern of Yiwu was lower in middle and surrounded by high; from 2000 to 2007, Yiwu's ecological security situation deteriorate from the surrounding rural central to the ecotone, and the state of northern is severe than southern. From the regional scale analysis we can know that the ecological security condition is relate to the geographical position of villages and towns, The closer the town near the center built up area, the lower the town's ecological security level. In the last 7 years, besides the ecological security of Chian, Fotang and Yiting has improved, various other towns have different degrees of deterioration, the ecological security difference among different towns is affected by many factors, such as population density, built up area, vegetation coverage, economical development and resources.Fifth, completed the ecological security assessment and early warning of Yiwu in 2015 based on the depth analysis of the evaluation result, during which involves the CA-Markov model to predict land use and the exponential regression model predictions of statistical indicators. The results showed that: Yiwu's ecological security index in 2015 is between 0.68 and 0.79; all belong to the more security early warning status, mainly due to the water environment and air quality of Yiwu in 2015 remained well, the overall improvement of ecological environment played a significant positive effect.