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Soilmoisturecontent,Soilmoisture:Ratioofliquidwatercontenttosoilinvolumeorweight,http:/www.habitat.adfg.state.ak.us/geninfo/kbrr/coolkbayinfo/kbec_cd/html/ecosys/physical/soils.htm,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DarkcolorgenerallyassociatedwithhighOMLandsatTM波段5和6与有机质负相关LandsatTMbands5and6havenegativecorrelationwithOM,SoilOrganicMatter,SoilOrganicMatter,OrganicmattercontentintheSantaMonicamountainsmappedusingAVIRIS(Palacios-Oruetaetal.1999),土壤纹理结构Soils:Texture,粘土,泥沙,砂,砾,土壤微粒大小,SoilTexture,Proportionofsand,siltandclayinasoil(orhorizon),usuallycalculatedas%weightforeachtypeofparticleThesepercentagesaredivideddifferentsoiltextureclasses,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。Liquidwaterabsorbssunlight1.4,1.9和2.7m波段可以用于估计土壤水分Thedepthsofthewaterabsorptionbandsat1.4,1.9and2.7mcanbeusedtoestimatesoilmoisture.,干土壤的光谱曲线BasicDrySoilSpectrum,粗砂,泥沙,不同纹理类型的湿土壤的光谱曲线SoilMoistureandTexture,Sinceclayeysoilholdswatermoretightlythansandysoil,thewaterabsorptionfeatureswillbemoreprominentinclayeysoilsgiventhesameamountoftimesincethelastprecipitationorwatering,粗砂,粘土,热红外遥感ThermalinfraredtechniquesThroughassimilation/modelingtogetroot-zonesoilmoisture微波遥感MicrowaveSARPassiveTop2-5cm,shallowerthan10cm,couldbemodelingtoroot-zonesoilmoisture可见光-近红外遥感Optical(visible/nearinfrared)Usingsolarradiationasadirectenergysource,isapassiveremotesensingmethodcoveringvisibleandnearinfraredIndirectlytoroot-zonesoilmoisture,土壤水分遥感方法Remotesensingsoilmoisture,3、微波土壤水分遥感Microwave,AdvantagesofMicrowaveRS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MicrowavemeasurementstronglydependentondielectricpropertiesofsoilwaterNotdependentonsolarillumination,Soils: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.,RadarRemoteSensingSoilMoisture,HYDROS(http:/www.skyrocket.de/space/doc_sdat/hydros.htm)Back-upESSPmissionforglobalsoilmoisture.L-bandradiometer.L-bandradar.Diedmission,Courtesy:TomJackson,USDA,SGP97,RadarPol:VV,HH(2)Vegetation(NDVI)atthehumidsiteneedslongertime(10days)torespondtosoilmoisturechangethanthatatthesemi-aridsites(5daysorless);(3)Thetime-seriesofroot-zonesoilmoistureestimatedbyalinearregressionmodelbasedondeseasonalizedtimeseriesaccountsfor4271%oftheobservedsoilmoisturevariationsforthethreesites;and(4)Inthesemi-aridregion,root-zonesoilmoistureofshrub-vegetatedareacanbebetterestimatedusingNDVIthanthatofgrass-vegetatedarea.,湿草地Humidgrassland,Estimatedversusobservedsoilmoistureatthe10cm,20cm,and50cmdepthsduringMaytoOctoberof20002003atthePrairieViewsite(TX)usingdeltamethod(leftpanel)andrawmethod(rightpanel).,估计的土壤湿度与实测土壤湿度的对比,半干旱草地Semi-aridgrassland,Estimatedversusobservedsoilmoistureat20cmdepthsduringMaytoSeptemberof20002003attheAdamsRanchsite(NM)usingdeltamethod(leftpanel)andrawmethod(rightpanel).,半干旱灌木Semi-aridshrub,Estimatedversusobserv