25684.基于modis數(shù)據(jù)的石羊河流域植被覆蓋時空變化研究

1、西北師范大學碩士學位論文基于MODIS數(shù)據(jù)的石羊河流域植被覆蓋時空變化研究姓名：李海亮申請學位級別：碩士專業(yè)：地圖學與地理信息系統(tǒng)指導教師：趙軍苗天寶200905????????????IIIABSTRACTSurfacevegetationhasfunctionswithslowingdownrunoffcombatingdesertificationpreventingsoilerosionsoon.Itplaysanimptant

2、roleintheprocessofenergyexchangebiogeochemicalcycleshydrologicalcycleinlsurface.MODISvegetationindexisafactofthebestindicatsbetweenstateofvegetationgrowthvegetationcover.Atthesametimeitistheimptantindicatabouttheseasonof

3、changehumanactivitiesaffect.Vegetationcoverageisaveryimptantecoclimaticparametersitisalsoacomprehensivequantitativeindicatsofcoveringthesurfaceconditionofplantcommunities.Wehavestudiedtheestimationofvegetationcoveragecha

4、ngeswhichwillplayanimptantroleinenvironmentalchangehydrologyecologyglobalchangeotherareas.InthispaperthestudyareaisShiyangriverbasinwhichisatypicalinlriverbasinofthearidsemiaridnthwest.FirstlyweextractMODISNDVIMODISEVIin

5、thisbasinwhichisdifferentintimespaceresolutionthroughtheGISsoftwareinthebasisofMODISdateswhenweanalyzesthetempalspatialvariationofvegetationindexacteristics.thenweestimatedthevegetationcoverageinthisbasinofdifferenttimes

6、paceresolutionthroughimprovedvegetationcoverestimationmodel.Wealsoanalyzedthedistributionofvegetationcoveracteristicsthedynamicchanges.Finallywediscussedthedrivingfactsofchangesinwatershedvegetationcoverreachedthefollowi

7、ngmainconclusions:FirstlythespatialdistributionofMODISvegetationindexesinthebasinwasaffectedbythenaturalconditionstheluseshowedsignificantgeographicaldifferences.Therearethreedifferentgeographicaldistribution:TheSouthern

8、Qilianmountains?centralplainsdistrict?thentherndesertarea.Vegetationindexesinvariousregionshavedifferentacteristicschangerules.Secondlyftheentirebasinvegetationindexcurvesoftheyeararesimilarinshapewithdownwardopeningseco

9、nddegreeparabolas?whosechangeswereinlinewiththebiologicalacteristicsofvegetationthechangesinphenology?whichshowedobviouslyseasonalpattern.Theprecipitationthetemperatureaffectthevegetationindexyearchangesaretheleadingfact