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ID:52540811
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时间:2020-04-09
《实习三 植被遥感-植被指数及其应用.ppt》由会员上传分享,免费在线阅读,更多相关内容在PPT专区-天天文库。
1、实习三植被指数及其应用实习要求一、直接由DN值计算植被指数;二、由反射率计算植被指数;三、比较两种方法计算的植被指数之间的差异,并提取一些典型地表的植被指数值。地类反射率水体城镇农田DN值计算反射率计算Infrared/RedRatioVegetationIndexThenear-infrared(NIR)toredsimpleratio(SR)isthefirsttruevegetationindex:Ittakesadvantageoftheinverserelationshipbetweenchlorophyllabsorptionofredradiantenergyandincre
2、asedreflectanceofnear-infraredenergyforhealthyplantcanopies(Cohen,1991).NormalizedDifferenceVegetationIndexThegenericnormalizeddifferencevegetationindex(NDVI):hasprovidedamethodofestimatingnetprimaryproductionovervaryingbiometypes(e.g.Lenneyetal.,1996),identifyingecoregions(Ramseyetal.,1995),monit
3、oringphenologicalpatternsoftheearth’svegetativesurface,andofassessingthelengthofthegrowingseasonanddry-downperiods(HueteandLiu,1994).Liu和Huete(1995)发展了“改进型土壤大气修正植被指数(EVI)”将背景调整和大气修正结合起来。EVI被简化为:EVI=2.5×(NIR-Red)/(NIR+6×Red-7.5×Blue+1)L为背景(土壤)调整系数,G为比例因子,C1,C2为拟合系数。MODIS算法中使用:大气影响与消除EnhancedVegetat
4、ionIndex通常在LAI反演应用中,使用修正的比尔定律来描述LAI与植被指数之间的关系。由于不同的植被类型与电磁波的相互作用可能差异较大,因此实际应用中都会针对不同的植被覆盖类型,分别建立反演模型。如:阔叶林:针叶林:LeafAreaIndexLandsatsensorMSS(LS-1-5)TM(LS-4/5)ETM(LS-6)ETM+(LS-7)Spectralbands(allbandsinµm)1)0.5-0.62)0.6-0.73)0.7-0.84)0.8-1.11)0.45-0.52VNIR2)0.52-0.60VNIR3)0.63-0.69VNIR4)0.76
5、-0.90VNIR5)1.55-1.75SWIR7)2.08-2.35SWIR6)10.4-12.5TIRP)0.52-0.90VNIR1)0.45-0.52VNIR2)0.52-0.60VNIR3)0.63-0.69VNIR4)0.76-0.90VNIR5)1.55-1.75SWIR7)2.08-2.35SWIR6)10.4-12.5TIRP)0.52-0.90VNIR1)0.45-0.52VNIR2)0.53-0.61VNIR3)0.63-0.69VNIR4)0.78-0.90VNIR5)1.55-1.75SWIR7)2.09-2.35SWIR6)10
6、.4-12.5TIRSwathwidth185km185km185km185kmSpatialresolution80m30mVNIR/SWIR120mTIR15mPAN,30mVNIR/SWIR,120TIR15mPAN30mVNIR/SWIR60mTIRRadiometricresolution6bit8bit9bit(8bittransmitted)9bit(8bittransmitted)Band-to-bandregistration0.2pixel(90%)0.2pixel(90%)0.2pixel(90%)Geodeticaccuracywithoutgroundco
7、ntrol500m(90%)1000m(90%)400m(90%)Datarate15Mbit/s85Mbit/s2x85Mbit/s2x75Mbit/sInstrumentmass64kg258kg288kgscanner,plus81kgAEM318kgscanner,plus103kgAEM,plus20kgcableharnessAveragepower50W332W490W590WTelescopeaper
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