| Economic development in human society is always accompanied by the destruction of the environm ent and the waste of resources. W ith the expansion of population and higher sta ndard of econom ic development, the destruction of land resour ces is in creasingly serious. Soil erosion is not an environmental problem that plagues a certain region but a problem that bothers the whole world, which is constantly affecting and restricting human production and life. Therefore, it is necessary to do a related study on the dynam ic changes of soil erosion to find, forecast and provide some solution s to the problem of soil erosion. The study, with the help of rem ote sensing and GIS and based on the theory of soil erosion, has m ade a study on the dynam ic changes of soil erosion for Longchuan basin.Longchuan basin, on the border of Yunnan province and Sichuan province, is the edge of Yunnan-Guizhou plateau with a complex topography, sharp altitude, large ravines and gullies criss-cross and serious soil erosion. In order to study the soil erosion in Longchuan basin, co mbined with the technology of rem ote sensing image processing, GIS platform, and GDEM database, the author adopts Landsat TM satellite remote sensing image as the data source to get the land use types, vegetation coverage and slope in the area during the periods of 2003, 2009 and 2015,then verified the result base d on the field data. Using Arcgis platform grid calc ulated soil ero sion data and based on the national water conservancy industry standard SL190-2007 issued by the m inistry of water resources, the author has made a classification of soil erosion intensity. Besides, the author has also done a deep study fo r the result of the erosion of the overall situation, the dynamic changes and the relationship between each factor. The main content of the research includes:Using TM image as data source extract of NDVI and with the skill of dichotom y, the vegetation coverage has been calculated. Combined with decision tree, the land use type has been put forward through the m ethod of supervised clas sification. Using the GDEM data, the gradient information has been got and cl assification assignment has been made. Combining various factors, the data of soil erosion in Longchuan basin during the three periods has be en calculated.Through the us e of GIS technology and statistical analysis technology to obtain the three period s of soil erosion of data for dynamic analysis and the calculation of the transfer matrix of soil erosion and annual variations of soil area, som e results have been obtained: the soil erosion type in Longchuan basin is given priority to m ild erosion and moderate erosion and the mild erosion is on the touch of moderate erosion. From 2009 to 2015, the developm ent degree of soil eros ion was higher than that of soil erosion from 2003 to 2009.Besides, there is an indispensable relationship between the transformation of soil erosion and the change of land use type and vegetation coverage. The increase of land and the decrease of forest land are the main human factors of soil erosion, and the decrease of precipitation in th e southwest region of Southwest China in 2010 is the main natural factor.In the end, based on the current situ ation and trend in Longchuan basin, a few suggestions for the measures of preventing soil erosion have been proposed. |
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