Simulation Of Land Use Change In Nanjing Based On CLUE-S Model

Global environmental change has caused human’s concern about land use and land cover.LUCC is the focus of research in global change science.Land use change simulation is the key research direction of LUCC.Understanding the driving mechanisms of land use and land cover is conducive to grasping future development.Nanjing,as an important central city in the east of China,economic development has driven the land use change of Nanjing,which brought great pressure to this city.Land resources are becoming more scarce with economic development.The studies of dynamic simulation of land use change might help relevant departments of Nanjing for better understanding the process of land use change,thus promoting more scientific decision-making and more sustainable development of land resources.Taking Nanjing as an example,this paper interprets remote sensing images in2005,2010 and 2017,and extracts five land types: forest land,water area,urban and rural construction land,cultivated land and other land.Using land use structure table,land transfer matrix and land use type transfer rate to analyze land use change in Nanjing from 2005 to 2017.Based on the development characteristics of Nanjing,the ten driving factors of land use changes were selected from the natural aspect and socioeconomic aspect.The driving factors of land use change in Nanjing were analyzed by Logistic regression method and the GM(1,1)model was used to measure the land demand in Nanjing.The CLUE-S model was used to simulate the land use change in Nanjing from 2010 to 2017.The spatial distribution of land use in Nanjing in 2030 under three different land use scenarios was predicted for natural growth scenarios,ecological conservation scenarios and urban rapid expansion scenarios.The main findings are as follows:(1)Land use change was relatively stable between 2005 and 2010.Land use has changed greatly from 2010 to 2017.Compared with 2010,the area of urban and rural construction land and forest land in Nanjing increased 54334.5 hectare in 2017,and the area of cultivated land,waters and other land decreased68889.56 hectare、4412.62hectare、9879 hectare.The increase in urban and rural construction land is mainly due to the reduction of cultivated land and other land.(2)The 100m×100m grid scale is the suitable scale for land use change simulation in Nanjing.Choosing the appropriate grid scale is very important for the simulation results.At this scale,the ROC value is the largest,and all value are greater than 0.7,indicating that the impact factors can explain the land use change in Nanjing at 100m×100m scale.(3)Based on the CLUE-S model simulation of land use change in Nanjing in2017,the simulated Kappa value reached 0.85,indicating that the CLUE-S model and parameters are applicable to the simulation of land use change in Nanjing.The simulation results can explain the distribution of land use patterns in Nanjing.(4)The paper sets the natural growth scenarios,the ecological protection scenarios and the rapid urban expansion scenarios for simulation of land use change in Nanjing.Under three different land use scenarios,land use changes in Nanjing are different.Under the natural growth scenario,the land types in Jiangning District,Pukou District,Qinshui District and Qixia District have changed greatly.In these areas,there is a large increase in urban and rural construction land and a large reduction in cultivated land.Under the rapid urban expansion scenario,the rate of urban and rural construction land use increased in Nanjing in 2030,especially in the urban and rural construction land area of Jiangning District,which is expanding along the edge of developed urban areas such as Xuanwu District,Qinhuai District and Yuhuatai District.The construction land is connected with the original construction land.Under the ecological protection scenario,ecological land such as forest land,waters and other land is protected.(5)Through the simulation of land use change in Nanjing,we know that the land use structure and layout are unreasonable in Nanjing.In the future land use process of Nanjing,the construction land increment should be strictly controlled,the red line of cultivated land should be adhered to,and the ecological space should be maintained.