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sur le développement des zones arides et semi-arides

Titre : Spatial and Temporal Evolution Characteristics and Driving Factors of Land Desertification in the Middle and Lower Reaches of Shule River From1987 to 2017

Auteur : 陈丽红；

Grade : Master’s Theses 2020

Université : Northwest Normal University

Résumé partiel
Desertification has become one of the most serious ecological and environmental problems in the world.And because of its wide distribution,it harms the natural environment,ecological environment,social economy and the survival and development of human beings,which has attracted the attention of the international community.It is of great significance for the control and prevention of desertification to carry out the research on the monitoring,driving factors and evolution rules of desertification,especially the analysis and research on the driving factors of desertification on this basis.The problem of desertification in the middle and lower reaches of Shule River is serious,and the ecological environment is fragile.Understanding the characteristics of desertification evolution and influencing factors is the premise to maintain and improve the regional ecological environment and ensure the social and economic development.Therefore,this paper takes desertification land in the middle and lower reaches of Shule River as the research object,based on Landsat5 TM、Landsat7 ETM+ and Landsat8 OLI remote sensing image data,extracts the Albedo and NDVI data of the middle and lower reaches of Shule River in 1987,1992,1997,2002,2007,2012 and 2017,constructs the differential index model(DDI)of desertification remote sensing monitoring,and analyzes its temporal and spatial dynamic change characteristics and influencing factors.The main findings are as follows :(1)In the time dynamic change,Between 1987-1992,1992-1997,1997-2002,2002-2007,2007-2012 and 2012-2017,surface albedo(Albedo)decreased,decreased,decreased,decreased,increased in the middle and lower reaches of the Shule River,the corresponding rates of change were-0.25%,-0.25%,-4.83%,-1.6%,-6.52%,2.55%,respectively ;Vegetation index(NDVI)showed a trend of decline,increase,increase,increase,increase and increase,with corresponding change rates of-5.95%,0.6%,0.89%,5.34%,14.83% and 0.24%,respectively.Desertification index(DDI)showed a trend of decreasing,decreasing,increasing,decreasing,increasing and increasing,and the corresponding change rates were-2.85%,-4.53%,22.68%,-3.02%,12.81% and35.77%,respectively.It can be seen that from 1987 to 2017

Mots clés : Middle and Lower Shule River； Remote sense； Desertification； Temporal and spatial variation； Cause analysis；

Présentation (CNKI)