Remote Sensing Monitoring And Driving Factors Analysis Of Water-Erosion Desertification In The Yunnan-kweichow Plateau Nearly Past 30 Years (1989-2016)

Land water-erosion desertification mainly occur in ecologically fragile humid regions,sub-humid and seasonal arid regions.The research on water-erosion desertification extraction in the above areas still needs to be further based on existing research.The Yunnan-Kweichow Plateau is a typical seasonal and arid ecologically fragile area.The water-erosion desertification is serious.Therefore,it is of great practical significance to study the large-scale water-erosion desertification in the Yunnan-Kweichow Plateau.In this paper,Landsat remote sensing data is used to extract the thematic information of water-erosion desertification classification in YunnanKweichow Plateau,and the spraatial-tempol change analysis is carried out.Relevant meteorological data,land cover data and social data are used to analyze the driving factors of water-eroded desertification on time scale and spatial scale.The main research results of this paper are as follows:(1)Based on Landsat data and GEODEM data,comprehensively consider the various factors affecting the development of water-erosion desertification,construct four indicators of vegetation coverage,inferior coverage,slope and valley density,and use the decision tree method to carry out water-erosion desertification classification and remote sensing in the region.Comparison with three indicators,two indicators,a single indicator and water-erosion desertification classification information obtained using the SVM method.The experimental results show that the four-indicator method has the highest accuracy,and its overall accuracy is 90.61%,and the Kappa coefficient is 0.8685.(2)The four-indicator decision tree was used to extract the thematic maps of water erosion desertification classification(severe,moderate,mild water-erosion desertification and non-desertification)from 1989 to 2016.The spatio-temporal analysis of four-indicator desertification in the Yunnan-Kweichow Plateau in the past 30 years has led to the following conclusions: The main distribution of desertification in the Yunnan-Kweichow Plateau can be divided into the area of the Dianguiqian area,the Wumeng Mountain area,the western Yunnan border area and the Red River area.The causes of water-erosion desertification vary from region to region;from 1989 to 2016,the water-erosion desertification in the Yunnan-Kweichow Plateau is generally expanding,but the area of water-eroded desertification in most parts of Guizhou Province has not changed much,and some regions have even experienced a slow decline;from 2010 to 2013,Yunnan The proportion of water-erosion desertification coverage in the Yunnan province has increased significantly,especially in the central Yunnan region;(3)Analysis of driving factors for water erosion and desertification in the YunnanKweichow Plateau in the past 30 years.On the time scale,comprehensive analysis of all nine driving factors,using the gray correlation model to analyze the main influencing factors of water erosion desertification,the precipitation of water-eroded desertification in Yunnan-Kweichow Plateau is mainly affected by rainfall of climatic factors,vegetation cover and cultivated land and bare soil area of LUCC factors,the GDP and population of human factors.On the spatial scale,using the geographically weighted regression model to calculate the driving mechanism of the impact factors on water-erosion desertification,the spatial elements added by the geographically weighted regression model overcome the defects of the traditional statistical model conditional assumptions,and the fitting effect is obviously improved.The three main influencing factors selected by the collinearity test are the annual precipitation of climatic factors,the vegetation coverage area of land cover factors,and the GDP of human activity factors.These three factors have a distribution of positive and negative intervals for the geographically weighted regression coefficients of water-erosion desertification,mainly concentrated between [-1,1] and normal distribution.Among the three factors,the absolute value of the factors on water-erosion desertification is rainfall,followed by GDP,and again the vegetation factor,indicating that the watererosion desertification in the Yunnan-Kweichow Plateau is mainly affected by rainfall,and the water erosion and desertification in the Yunnan-Kweichow Plateau is a comprehensive The process is the result of the interaction of natural factors and human activities.The effects of precipitation,vegetation area and GDP on water-eroded desertification are mainly negatively correlated.The main areas of precipitation and water-eroded desertification are mainly distributed in the central Yunnan,southwestern Yunnan and western Yunnan.The main regional distribution of vegetation area and water-erosion desertification in the southwestern Guizhou,central Guizhou and Dianguiqian area,the main areas of GDP and water-erosion desertification are distributed in the western Yunnan and Dianguiqian area.(4)Based on the above summary,the extraction method of water-erosion desertification in Yunnan-Kweichow Plateau,using the index system combined with the decision tree method,the water-erosion desertification classification results extracted by using four indicators is better than the method using three indicators,two indicators,and a single indicator,and Better than the SVM method.The results of water erosion and desertification classification are mainly concentrated in the area of the Dianguiqian area,the Wumengshan area,the west border area of the Yunnan and the area along the Red River.The driving factors of water-erosion desertification are analyzed from the time scale and spatial scale.The results show that water erosion and desertification in Yunnan-Kweichow Plateau is a complex result of the combination of natural and human factors.