第10章4-流域数据获取-土壤水分遥感

4土壤水分遥感RemoteSensingofSoilMoisture第十章流域数据获取内容•1土壤水分概述•2土壤光谱特征•3微波土壤湿度遥感•4可见光-近红外土壤湿度遥感•5热红外土壤湿度遥感1、Whatissoilmoisture?•土壤水分：土壤微粒之间所储的水分Soilmoistureisthewaterthatisheldinthespacesbetweensoilparticles.•表层土壤水分：土壤上层10cm内的水分Surfacesoilmoistureisthewaterthatisintheupper10cmofsoil.•根带土壤水分：植被可用的，土壤上层200cm内的水分rootzonesoilmoistureisthewaterthatisavailabletoplants,whichisgenerallyconsideredtobeintheupper200cmofsoil.•土壤水分：SoilMoisture,soilwater–土壤湿度：土壤含水量SoilmoisturecontentProfileofSoilMoisture-100-90-80-70-60-50-40-30-20-1000.050.100.150.200.250.30SoilMoistureSoilDepth(cm)Soilmoisture:Ratioofliquidwatercontenttosoilinvolumeorweight标准土壤剖面StandardSoilProfile腐殖质矿物质微粒底土基岩AnNRCSsoilscientistplacingapiezometer流体压力计inthegroundtomeasuresoilmoisture土壤湿度计FactorsInfluencingSoilReflectance•mineralcomposition矿物构成•soilmoisture土壤湿度•organicmattercontent有机质•textureandroughness粗糙度•Salinity含盐度2、土壤遥感的光谱特征IronOxide氧化铁（铁矿石）无氧化铁的壤土有氧化铁的壤土氧化铁IronOxide•IroncontentintheSantaMonicamountainsmappedusingAVIRIS(Palacios-Oruetaetal.1999)土壤有机质Soils:OrganicMatterContent•有机质影响颜色、热容量、含水能力、营养物交换、结构、侵蚀。OMaffectssoilcolor,heatcapacity,waterholdingcapacity,nutrientexchange,structure,anderodability•暗色土壤含较高的有机质DarkcolorgenerallyassociatedwithhighOM•LandsatTM波段5和6与有机质负相关LandsatTMbands5and6havenegativecorrelationwithOMSoilOrganicMatterSoilOrganicMatter•OrganicmattercontentintheSantaMonicamountainsmappedusingAVIRIS(Palacios-Oruetaetal.1999)土壤纹理结构Soils:Texture0.0020.050.10.250.512mmParticlesizerelativetoagrainofsand0.15mmindiameterSandSiltClayClaySiltSandv.finefinemediumcoarsev.coarseGravel0.0020.060.22mmClaySiltSandGravelStonesfinemediumcoarse0.0060.020.60.15mmfinemediumcoarse76.20.0020.22mmClaySiltSandGravel0.02finecoarsea.SoilScienceSocietyofAmericaandU.S.DepartmentofAgricultureSoilParticleSizeScaleb.MITandBritishStandardsInstitutec.InternationalSocietyofSoilScience粘土泥沙砂砾土壤微粒大小SoilTexture•Proportionofsand,siltandclayinasoil(orhorizon),usuallycalculatedas%weightforeachtypeofparticle•Thesepercentagesaredivideddifferentsoiltextureclasses100908070605040302010100100908070605040302010908070605040302010Clay(%)Sand(%)Silt(%)readreadreadClaySiltSandloamysandsandyloamLoamsandyclayloamsiltyclaysiltyclayloamclayloamsandyclaysiltloam粘土砂泥沙%clay，%silt,%sand,%粘土、%泥沙、%砂土壤纹理类型Loam壤土土壤水分对光谱的影响SoilMoisture•水对阳光波段是吸收的。Liquidwaterabsorbssunlight•1.4,1.9和2.7m波段可以用于估计土壤水分Thedepthsofthewaterabsorptionbandsat1.4,1.9and2.7mcanbeusedtoestimatesoilmoisture.specularreflectanceincidentenergyinterstitialairspacespecularreflectancesoilwatera.b.drysoilwetsoilvolumereflectancespecularreflectanceincidentenergy干土壤的光谱曲线BasicDrySoilSpectrum2060100PercentReflectance0.50.71.11.30Wavelength(m)80400.91.51.71.92.12.32.5SiltSand1030507090粗砂泥沙不同纹理类型的湿土壤的光谱曲线SoilMoistureandTexture•Sinceclayeysoilholdswatermoretightlythansandysoil,thewaterabsorptionfeatureswillbemoreprominentinclayeysoilsgiventhesameamountoftimesincethelastprecipitationorwatering2060PercentReflectance0.50.71.11.30400.91.51.71.92.12.32.522?32%103050Sand20600.50.71.11.30Wavelength(m)400.91.51.71.92.12.32.535?40%1030502?6%0?4%moisturecontent5?12%Claya.b.PercentReflectanceSandSandSandClayClayClay粗砂粘土•热红外遥感Thermalinfraredtechniques–Throughassimilation/modelingtogetroot-zonesoilmoisture•微波遥感Microwave–SAR–Passive–Top2-5cm,shallowerthan10cm,couldbemodelingtoroot-zonesoilmoisture•可见光-近红外遥感Optical(visible/nearinfrared)–Usingsolarradiationasadirectenergysource,isapassiveremotesensingmethodcoveringvisibleandnearinfrared–Indirectlytoroot-zonesoilmoisture土壤水分遥感方法Remotesensingsoilmoisture3、微波土壤水分遥感MicrowaveAdvantagesofMicrowaveRS优点•全天候，大气透明Transparentatmosphere,allweathercoverageindecimeterrangeofEMR•植被半透明Vegetationsemitransparent•依赖土壤水介电常数Microwavemeasurementstronglydependentondielectricpropertiesofsoilwater•NotdependentonsolarilluminationSoils:MoistureContent湿度•土壤水分直接与表层土水分有关Theoretically,soilmoistureisdirectlyrelatedtosurfacesoilmoisturecontent。•综合孔径雷达估计土壤湿度受下列因素影响SARestimatesofsoilmoisturearealsoinfluencedby:：–粗糙度Roughness–地形Topography–植被密度vegetationdensity–含盐量Salinity雷达遥感土壤水分SoilMoisturefromRADAR•高介电常数（高湿度）产生高的雷达回波。Higherdielectricconstants(moremoisture)yieldshigherRADARbackscatter.下半部分有降雨，上半部分无降雨Melfort,Saskatchewan,Canada,ERS-1:Rainfallfellontheareainthelowerhalfoftheimagebutnotontheupperhalf.RadarRemoteSensing—SoilMoisture•HYDROS()–Back-upESSPmissionforglobalsoilmoisture.•L-bandradiometer.•L-bandradar.–Diedmission-98.5-98.0-97.535.035.536.036.5-98.0-97.5-97.001020304050SouthernGreatPlainsHydrologyExperiment(SGP97)SurfaceSoilMoistureDerivedFromRemotelySensedMicrowaveDataJune30July1July2July3SoilMoisture(%)Latitude(Degrees)Longitude(Degrees)5040302010035.035.536.036.537.0ChickashaElRenoLamontOklahomaCityChickashaElRenoLamontOklahomaCityChickashaElRenoLamontOklahomaCityChickashaElRenoLamontOklahomaCityJune30NASALandSurfaceHydrologyProgram-98.5-98.0-97.535.035.536.036.5-98.0-97.5-97.001020304050Southe