Research On The Coupling Relation Between Expansion Of Built-up Areas And Ecological Bearing Built-up Areas And Ecological Bearing Capacity Of Baotou City Based On GIS And RS

The relationship between urbanization and ecological environment is an important part of the study of global environmental change,which is of great significance to the sustainable development of cities and the harmonious development of man and nature.As 3 part of it,the study of urban expansion and ecological carrying capacity plays an important guiding role in promoting urbanization and achieving the great goal of ecological civilization in China.In order to explore the coupling coordination relationship between urban expansion and ecological carrying capacity,this paper used ENVI and GIS spatial analysis technology to obtain the main built-up areas in downtown Baotou City,combined with four periods Landsat/OLI remote sensing image data and night light data which spanning 12 years.Then we used a variety of parameter indicators to analyze the morphological characteristics of built-up areas concretely,so as to measured and analyzed the spatial morphology of built-up areas.At the same time,we used the improved ecological footprint method to calculate and analyze the changes of ecological carrying capacity in Baotou city center.Based on the above,we finally analyzed the coupling relationship between urban expansion and ecological carrying capacity.The main research contents and conclusions were as follows:1.This study used the method of urban boundary definition to extract the polygon of built-up area.ENVI 5.3 software is used to preprocess remote sensing images in 2006,2011,2016 and 2018 to eliminate the influence of atmosphere on pixel gray value.The land use situation in Baotou city center is interpreted by means of supervised classification,and the land use in Baotou city is divided into six categories including cultivated land,woodland,grassland,water area,construction land and unused land.The night light data is processed by logarithmic transformation,and the distribution of radiation brightness value is stable and easy to distinguish between built and non-built areas.The statistical data reference comparison method obtains the appropriate threshold of night light data and divides the urban built-up area based on night remote sensing image.Using ArcGIS,SPSS,EXCEL and other software,this paper analyzed the evolvement characteristics of the spatial form of the built-up area in Baotou downtown area.We then analyzed them quantitatively,applying shape index,compactness index,transfer of urban gravity center,fractal dimension expansion direction,expansion speed and expansion intensity.2.The ecological footprint method of improving yield factors was used to study the ecological carrying capacity of Baotou downtown from 2006 to 2018.The per capita ecological footprint of Baotou downtown is larger than the ecological carrying capacity from 2006 to 2018.The ecological carrying capacity decreases year by year while the ecological deficit increases first and then decreases.From 2006 to 2018,in addition to the annual decrease of water ecological deficit in the central urban area of Baotou City,the ecological deficit of cultivated land,woodland,grassland,construction land,fossil fuel land and other land types in Baotou downtown area increased first and then decreased.The proportion of fossil fuel land in ecological footprint was the highest,followed by greassland,cultivated land,water,woodland and construction land.The proportion of cultivated land and construction land in ecological carrying capacity was the highest,followed by woodland,grassland,fossil fuel land and the smallest water area.3.Study on the relationship between spatial expansion and ecological carrying capacity of the built-up area of Baotou City.It includes the comprehensive order analysis of ecological carrying capacity and built-up areas expansion,the construction and analysis of coupling degree model,and the construction and analysis of coupling coordination degree model.The coupling degree between ecological carrying capacity and built-up area expansion in Baotou City increased from 0.607 in 2006 to 0.980 in 2011,and then dropped to 0.768 in 2016.Finally,it rose back to 0.894 in 2018.The coupling results developed from running-in stage to coordinating coupling stage,and then it goes back to regressing rubbing development stage from coordinating coupling stage,which belonged to coordinating coupling stage in 2018.The coordination degree decreased from 0.645 in 2006 to 0.477 in 2016,and gradually increased to 0.622 in 2016-2018.The coordinated degree values from 2006 to 2018 are all in moderate and transitional coordination areas.The above analysis shows that the built-up areas and ecological environment carrying capacity of Baotou City are basically in a relatively coordinated state.