Evaluation And Prediction Of Land Ecological Security Based On TOPSIS-RBF Model

Land plays an irreplaceable role in the social economic activities.But along with the rapidly development of society,the acceleration of urbanization process,and the constantly advancing of the industrialization and modernization,a series of land ecological problems have appeared,such as land pollution,land degradation and so on,which seriously affect the sustainable utilization of land resources.Therefore,carrying out the land ecological security research,making rational evaluation of land ecological security,and putting forward the optimized proposal feasible is necessary at this stage.It has great significance to ensure the harmonious development of nature,economy and society,to promote sustainable development of land resources,and to promote the construction of national ecological civilization.Taking Yantai city,one of the central city of Shandong Peninsula and the important port city of Bohai as the study area,on the basis of relevant research at home and abroad on land ecological security,determining weight by a combination of subjective analytic hierarchy process(AHP)and objective entropy method,the article,firstly evaluated the land ecological security situation of Yantai city by TOPSIS model,and obtained the objective and accurate evaluation results.Then on this basis of the results by TOPSIS model,the article pridicted the land ecological security situation by the high simulation of radial basis function neural network model RBF model.The main conclusions are as follows:(1)The evaluation of land ecological security in Yantai.Overall,the land ecological security level of Yantai City kept upwards trend from 2000 to 2014.The D+ gradually became smaller and tended to the positive ideal solution,while Dwas generally showed an increasing trend,gradually deviated from the negative ideal solution.The degree of C increased from 0.3863 in 2000 to 0.6023 in 2014,with a growth of 0.2160 and land ecological security level improving from "relative unsafety" to the level of "relative safety".On the development trend of land ecological security,the value increased slightly from 2000 to 2001,with the only negative factor: the amount of application of pesticide.The value declined slightly from 2001 to 2004,with the negative factors increasing and the biggest affected factors by the urbanization and the per capita arable land.The value increased significantly from 2004 to 2013,with a pretty large positive effect,but the negative effect was also obvious,in which the waste-water load,the urbanization,the construction land,the pesticides and other factors played negative role together.The value declined slightly again from 2013 to 2014,with a great influence by the effective irrigation caused by drought.The development of land ecological security reflects that the problems from 2000 to 2014 mainly exist in the urbanization expansion,the reduction of arable land,the construction land expansion,the waste-water load,the effective irrigation,the food security,the non-point source pollution of pesticides and fertilizers,which will be important problems need to be urgent solved in Yantai in the future.(2)The prediction of land ecological security in Yantai.The land ecological security in Yantai will continue maintaining a slow rising from 2015 to 2020,as the state from 2004 to 2013,with a score increasing from 0.6096 to 0.7122,slowly developing towards the state of safety.On the development of the three subsystems in the evaluation of land ecological security,the grade of the land ecological safety pressure subsystem will maintain in a state of relative unsafety from 2015 to 2020,with an ecological security value between 0.33 to 0.29,but the trend of decreasing will be gradually slowly,reflecting that the controlling of the ecological load and the protection work on ecological security is initially effectiveness recent years.The land ecological security of state subsystem will maintain in the slowly rising trend,with an ecological security value from 0.58 to 0.68,but the expansion of construction land and cultivated land area decreases still can't be underestimated.The score of land ecological security of response subsystem will decline slightly from 2015 to 2016,and will rebound in 2017,with a state of rising but trend gradually slow which happened before in response subsystem.Although the land ecological security of Yantai city will develop slowly towards the safety state for a period of time in the future,but with a hardly underestimated effect of ecological load,there is still a gap from the land ecological safety state of Yantai to the state of safety.In the future,we need pay more attention to land ecological security protection,striving to achieve safety state as soon as possible.