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NDVI)))以甘肃省张掖市甘州区为例周兆叶,储少林,王志伟,陈全功(,730020):为了分析张掖市甘州区自1987-2006年19年间的植被覆盖的变化,以归一化植被指数(NDVI)和植被覆盖度遥感定量模型为基础,以1987年2006年2期的TM影像和张掖市1B10万地形图为数据基础,提取两期的植被覆盖等级图,定量的分析该地区植被覆盖度的变化情况结果表明:近19年来,该区的植被盖度总体略呈下降趋势,荒漠化草地等植被覆盖状况较差的地区植被退化较为严重,绿洲地区的植被覆盖较为稳定,部分地区植被盖度呈上升趋势:甘州区;NDVI;植被覆盖;遥感:TP79:A:1001-0629(2008)12-0023-07*,,/0[1],,(),[2],,,,,,,[3](theNor-malizedDifferenceVegetationIndex,NDVI)ND-VI=(NIR-VIS)/(NIR+VIS),NIR,VIS,,,))),TM,,ERDASIMAGINE9.0ArcGIS9.1,,0~255,,,1,100b6c~100b52c,38b32c~39b24c,,,3698km2))),(),[4],,20%,,2512Vol.25.No.12PRATACULTURALSCIENCE2312/2008*:2008-01-08:(1982-),,,EËmail:zhouzhaoye2006@163.com:,[5]22.1数据来源1987820068TM1B102,1B102.2遥感图像预处理:1B10,ERDASIMAGINE9.0,,,0.5:,,:,ArcMap9.1,:,,,[6]200619872.3NDVI的计算及其与土地利用类型转换2.3.1NDVINDVI,NDVI[7]NDVI-1~+1,,NDVI,0;,NDVI,0.7;[7]NDVI,[8,9],NDVIERDASIMAGINE9.0indicesTMNDVI,NDVI(1)124PRATACULTURALSCIENCE(Vol.25.No.12)12/20082.3.2NDVI,ND-VI[10],,,[11,12],,[13],MDVI0~255=NDVI-NDVIminNDVImax-NDVImin@255,NDVI0~2550~255;NDVIminNDVImaxNDVI0~255NDVI0~2550~128,,:;NDVI0~255129~255,,,[14,15]2005))),/0,/0,/0[16,17],[18],1,0~255NDVI,21191~25560%156~19030%~60%139~15515%~30%129~1385%~15%1285%22512/2008(2512)2.2计算各级各时相植被覆盖的面积1~5,,,ArcMap9.122:19,,46.08%,,36.32%53.51%,54.81%37.01%46.32%,,2.3不同等级植被覆盖的动态变化ArcMap9.1TabulateArea,2,1987-20062198720061987(km2)(%)2006(km2)(%)(km2)(%)139.243.7762.921.70-76.3254.81600.8216.25819.0722.15218.2536.32493.9213.36311.128.41-182.8137.011279.9934.61687.0518.58-592.9546.321184.2232.021817.8649.16633.6353.5134:,,1/3,,106.97km2,173.19km2,48.75%,162.50km2,,760.56km2,101.76km231987-2006(km2)(%)(km2)(%)(km2)(%)(km2)(%)(km2)(%)11.047.936.036.011.522.34.370.32.430.2104.9576.4394.5465.7173.1935.192.047.351.854.414.0211.1106.9717.893.2918.756.504.441.933.53.892.849.218.2162.5032.7364.1428.5101.768.62.501.814.162.355.3211.2760.5659.5986.9283.341987-2006(km2)125.36206.37402.53913.47197.96(km2)54.35422.03219.42317.3683.25(km2)104.95106.97173.19760.56101.76(%)83.7251.8343.0383.2651.40(km2)36.03173.19106.97162.50760.52(%)66.2941.0448.7551.2091.3526PRATACULTURALSCIENCE(Vol.25.No.12)12/200833.1各时相各覆盖等级的总体变化,,,2:,1987139.24km2200662.92km2,54.81%19871184.22km220061817.86km2,53.51%,,37.19%,,,,218.25km2,36.32%,,3.2不同等级植被覆盖变化的动态分析:¹,198776.4%º,,,34.3%,,17.8%,,,»81.3%,,35.1%,,32.7%,¼71.5%,,59.5%,,½16.7%44.1自然因素4.1.1,,,,,,,50,,[19]4.1.2,760.56km2,21%,1987)2001551987-2006mm1987143.8199776.61988156.41998149.91989109.4199987.71990138.32000126.2199185.62001114.91992130.72002148.21993195.52003127.81994128.8200482.41995127.02005165.41996136.42006121.4,331987-2006,1987-2001,,2712/2008(2512),,4.2河流的影响,,12.87~23.12m3,,,,61987-2006m3198715.7199414.1198817.3199515.4198923.1199618.1199015.9199713.9199112.9199821.6199213.1199916.2199318.0200014.641987-20004.3人类活动及其政策的影响4.3.1,1987,40.698,200650.6558,24.5%,,20809010,1600hm2,,,,;,,,[19],,,,19871184.22km220061817.86km2,53.51%,,[20]4.3.2,1999,,20021.385hm2,,5,,,,,:;;;,[1].()[M].:,1980.139-145.28PRATACULTURALSCIENCE(Vol.25.No.12)12/2008[2].)))[J].,2004,18(1):159-160.[3],.[J].(),2006,34(9):163-166.[4],,.[M]..:,2002.122-227.[5]..[D].:,2004.[6],,,.ERDASIMAGINE[M].:,2003.110-113.[7],,,.NDVI:[J].,2006,13(6):179-181.[8],,,.1982-2000[J].,2007,22(3):397-398.[9]TobyN,Carlson,Davidaripley.OntheRelationbe-tweenNDVIfractionlvegetationcoverandleafareaindex[J].RemoteSensingofEnvironment,1997,62:241-252.[10]Yang,Prince.Remotesensingofsavannavegetationcoverfractionestimatedfromsatellitedata[J].In-ternationalJounnalofBiometeorology,2000,21(2):177-191.[11],,,.)))NOAA[J].,1998,2(3):205-210.[12],.[J].,2007,24(4):27-30.[13],,.[M].:,1998.345-349.[14],#.NDVI[J].,2002,18(1):23-26.[15].[M].:,2003.387-398.[16].[M].:,2000.40-42.[17].[M].:,1995.118-130.[18],.[J].,1994,11(3):10-11.[19],.[J].,2008,17(1):93-99.[20].)))[J].,2005,26(2):43-47.AnalysisofvegetationcoveragechangebasedonNDVI)))AcasestudyinGanzhouarea,Zhangyecity,GansuZHOUZhao-ye,CHUShao-lin,WANGZh-iwei,CHENQuan-gong(KeyLaboratoryofGrasslandAgroecosystem,MinistryofAgriculture,CollegeofPastoralAgricultureScienceandTechnology,LanzhouUniversity,Lanzhou730020,China)Abstract:InordertoanalyzethedynamicchangeofvegetationcoverageinGanzhouareafrom1987to2006,TMimagesof1987,2006and1B100000topographicmapsofZhangyecitywereusedtoextracttwolevelsofvegetationcoveragemaps,thevegetationcoveragechangesinthisregionwasanalyzedquantitativelybymeansofvegetationindex(NDVI)andquantitativeremotesensingmodelonvegeta-tionfraction.Theresultsshowedthatthetotalvegetationcoveragedeclinedoverallthelast19years,theareasofpoorvegetationconditionssuchasdesertificationgrasslanddegradedseriously,vegetationcoverageofoasiswasstable,someareasevenincreased.Keywords:Ganzhouarea;NDVI;vegetationcoverage;remotesensing2912/2008(2512)