DEM-based Study On Potential Energy Information Entropy Of Watershed Geomorphic System And Its Landform Evolution Significance

The Loess Plateau is the most concentrated and largest area of loess distribution on the earth.It is also one of the regions with the most serious soil erosion and the most ecologically fragile areas in the world.The evolution process of the Loess Plateau is affected by many factors,making its evolution process very complicated.The evolution of the geomorphic system in the Loess Plateau is not only closely related to its geomorphological morphology,but also closely related to the internal material and energy migration and distribution laws.However,most of the previous studies focused on the geomorphic,erosion and development process of the geomorphic system of the Loess Plateau.The energy migration and its distribution in the watershed geomorphic system are rarely studied in depth.Therefore,based on the viewpoints and methods of system theory and information entropy,this paper proposes the concept and calculation method of potential energy entropy of watershed landform,and uses DEM related theories and methods to study the geomorphic evolution of the watershed geomorphic system and the spatial variation of the internal potential energy of the system.The research results reveal the formation mechanism and evolution law of the small watershed in the Loess Plateau,and further reveal the soil erosion characteristics and spatial differentiation pattern of the small watershed in the Loess Plateau,and guide the soil and water conservation,ecological restoration and regional sustainable development and small watershed integration on the Loess Plateau,which has important theoretical significance and good application prospects.In this paper,the nine-stage DEM data obtained by simulating the geomorphological evolution of the Loess Plateau is used to calculate the entropy of the potential energy information entropy of each period of data,and the spatial distribution and evolution laws of the potential energy information entropy of the watershed geomorphic system are deeply analyzed and studied.The erosion evolution process of the geomorphic system of the Loess Plateau is studied from the unique perspective of the potential energy change law of the watershed geomorphic system.The main results and conclusions are as follows:(1)Based on the theory and method of information entropy and DEM,the concept of potential energy information entropy of watershed geomorphic system is proposed.Based on DEM splitting principle,the calculation method of potential energyinformation entropy is proposed,which is a useful supplement to the existing geomorphological research method,with important theoretical significance.(2)Using the 9-stage DEM data formed during the evolution of loess landform under the conditions of indoor artificial rainfall test,the change law of potential energy information entropy in the process of erosion-based watershed geomorphology is studied.The results show that the potential energy information entropy of the watershed geomorphic system shows the overall change characteristics of decreasing first and then increasing during the process of the geomorphology evolution.Compared with the traditional hypsometric integral,the potential energy information entropy can better reflect the geomorphic erosion characteristics and geomorphological development characteristics of the watershed geomorphic system.(3)By extracting the sub-watershed in each period of DEM data,the potential energy information entropy of each sub-watershed system is calculated,and the spatial distribution characteristics of the internal potential energy information entropy of the watershed geomorphic system are studied.The results indicate that the potential energy information entropy of the watershed geomorphic system shows an overall spatial distribution pattern with a large entropy value near the main channel and a small entropy value near the secondary watershed.The spatial distribution characteristics have obvious main channel position indication function.(4)The research on potential energy information entropy and elevation change and river development in the watershed geomorphic system shows that the potential energy information entropy can better reflect the erosion characteristics of the watershed geomorphic system during the geomorphological evolution and can reflect the ordering of river development.