Ecological Risk Assessment Of Coastal Wetland Cities In The Yangtze River Delta Based On Remote Sensing And Fuzzy TOPSIS

The coastal wetland is the main part of the coastal areas.Coastal wetlands beautify the ecological environment and provide many facilities and resources for the economic and social development of the coastal cities.With the acceleration of urbanization in the coastal areas of China,the increase of population,reclamation,land occupation,large amount of water and pollution discharge seriously destroy the ecological health of coastal wetlands.This paper chooses the coastal wetlands and cities in the estuary of the Yangtze River Delta to evaluate the ecological risk of coastal cities.In this paper,we first used the remote sensing to interpret the land use types of coastal wetland cities in the Changjiang Estuary.Using the remote sensing images of 2001 and 2015 to interpret the land use in the coastal area of the Yangtze River Delta during 15 years.It is convenient to observe the land use change directly and to provide the data base for the subsequent ecological risk assessment.According to the characteristics of the environmental ecology and economic development of the study area,the cities are combined with the coastal wetlands,taking the cities as the evaluation units.Based on AHP-PSR model,the evaluation index system of coastal city ecological risk is established,and the weight of evaluation index is obtained by using objective entropy weight method.The index was evaluated by fuzzy TOPSIS(Technique for Order Preference by Similarity to Ideal Solution)comprehensive evaluation method,then determining the risk index of the studied cities,dividing Risk classification ranking the risk levels among cities,analyzing the reasons of the ranking results,And puting forward reasonable suggestions to protect the coastal wetland cities ecology.The innovation of this paper lies in the study of coastal wetland city ecological risk assessment,the combination of coastal wetlands and cities,analysing ecological risk level changes based on the spatial span and time span.The established ecological risk assessment index of coastal wetland cities provides a reference for ecological risk assessment of similar areas.The fuzzy TOPSIS method is applied to the assessment,and the uncertainty of data statistics is fully considered,so that the evaluation results are more objective and convincing.