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植物生态学报 植物生态学报 2008
DETECTINGDESERTIFICATIONPROCESSESUSINGTMANDETM+DATA,NORTHOFISFAHAN,IRANDOI: 10.3773/j.issn.1005-264x.2008.02.009, PP. 328-335 Keywords: desertification,remotesensing,Isfahan,Iran,fuzzylogic,postclassification Abstract: ？AimsDesertificationresultsinecologicalandbiologicaldiminutionoftheearth,andcanhappennaturallyorcausebyanthropogenicactivities.Thisprocessespeciallyaffectsaridandsemi-aridregions,suchastheIsfahanregion,wherethespreadofdesertificationisreachingcriticalproportions.TheaimofthisstudyistouseremotelysenseddatatoreviewthetrendofdesertificationinthenorthernofIsfahan,Iran.MethodsMulti-temporalimageswereemployedtoevaluatethetrendofdesertification,specificallytheTMandETM+dataofSeptember,1990andSeptember,2001.Geometricandradiometriccorrectionswereappliedtoeachimagepriortoimageprocessingandsupervisedclassification,andvegetationindiceswereappliedtoproducealandusemapofeachimageinnineclasses.Thelanduseclassificationsinthetwomapimageswerecomparedandchangesbetweenlanduseclassesweredetectedoverthe11yearperiodusingafuzzyandpost-classificationtechnique.ImportantfindingsThemapsandtheircomparisonwithfalsecolorcompositeimagesshowedthedifferencesefficiently.Withthefuzzyandpost-classificationmethodthelandusechangesweresitedonthemap.Fuzzyconfirmed53%changedareaand47%unchangedareasinthestudyregion.Theresultsverifythedesertificationexpansioninthestudyareas.Becauseofpoorlandmanagement,agriculturallandsconvertedtodesertandabandonedareas,andsomemarginalpasturelandshadtobechangedtoagriculturallandwhicharedesertificationspreadingaccordingtoUnitedNationsConferenceonDesertification(UNCOD).Alsofarmlandandpastureshavebeenconvertedtourbanandindustrialareas,andtherangelandshavebeenspoiledduetoopencastmineexcavations.Withtheminemarginserodingaswellastheirdebrisaccumulatingonthepasturelands,desertificationhasbecomeworse.Threeareasofless-elevatedmountainshaveremainedunchanged.Thisstudyconfirmedthattheanthropogenicactivitiesacceleratedthedesertificationprocessandseverelyendangeredtheremainingareas.
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