旱情遥感监测研究进展与应用案例分析

1007-4619(2011)06-1315-16JournalofRemoteSensing遥感学报Received:2010-09-27;Accepted:2011-01-07Foundation:NationalHighTechnologyResearchandDevelopmentProgram(No.2009AA12Z101);KeyProjectofKnowledgeInnovationProgram,ChineseAcademyofSciences(No.KZCX2-YW-Q03-07)Firstauthorbiography:WANGLitao(1979—),male,associatedprofessor.Hisresearchinterestsaretheremotesensingapplicationsonhazardandenvironment.E-mail:[e-mail]graphy:WANGShixin(1965—),male,professor.Hisresearchinterestsaretheremotesensingapplicationsonhazardandenvironment.Hehaspublishedover40academicpapersandwritten2monographs.E-mail:[e-mail]1INTRODUCTIONDroughtisanaturalphenomenonofrelativewaterdeficiency,frequentlyoccursthroughouttheworldandinvarioushistoricalevents.Itwouldcauseharmtocropgrowthanddecreaseagricul-turalproduction.Theseveredroughtshouldcausetheshortageofdrinkingwaterandaffectthepeopleliving,industrialproductionandothersocio-economicactivities.InChina,theobviousmonsoonclimateandtheuneventemporal-spatialdistributionofprecipita-tionleadtofrequentoccurrenceofdroughtthatcausesseriouslyef-fectonagriculturalproductionandpeople’slives.Innorthernforestregion,droughtcouldmakefireoccurfrequentlyandbedifficulttocontrol.Forthedroughtwithcharacteristicsoflong-timecontinuingandlarge-scalespreading,real-timedynamicmacromonitoringin-formationisimportantfordrought-preventingdecisions.Inrecentdecades,Remotesensinghasthecapacityofrapid,economicalandmacroscopicdata-obtained.Itprovidesanimportanttechni-calmeansanddatasourcesforthedroughtmonitoring,whichwillmakeuptheshortageofmonitoringdroughtbasedonmeteorologi-calstationdata.Inthispaper,droughtmonitoringmethodsusingremotesensingareoverviewedandclassified,includingthemonitoringprinciple,applicabilityandadvances.Andthen,anapplicationcaseisintro-ducedwithrespecttothedroughtsituationoccurredinspring,2010inSouthwestChina.Intheapplication,adroughtmonitoringmeth-odcombinedwithGlobalVegetationMoistureIndex(GVMI)andShortwaveAngleNormalizedIndex(SANI)isusedandanalyzedbasedonremotesensingdata.2REMOTESENSINGMONITORINGMETHODSFORDROUGHTBasedondifferentassessmentconsiderations,thedroughtsitu-ationcanbedividedintometeorologicaldrought,hydrologicaldroughtandagriculturaldrought.Thecorrespondingevaluationin-dicatorsincludethreeaspects:precipitationindicators,soilmoistureindicatorsandcropwaterbalanceindicators(Li,2001).Withthedevelopmentofremotesensingtechnologyanddeepstudytothequantitativeretrievaltechnology,anumberofsurfaceparametersandthermalinformationcanbeextractedfromremotesensingdata,whichprovidesanimportanttheoreticalbasisfortheapplicationofmonitoringdrought.Duringthecourseofdroughtoccurrence,thesoilandvegetationaremoreimpacted.Sothesoilmoisture,eva-potranspiration,thevegetationgrowthandcanopywatercontentofvegetationareusedtoevaluatethedroughtsituation.Inpresentresearchesandapplications,fourkindsofmonitoringmethodsbasedonremotesensingarecommonlyused:soilthermalinertiaAdvancesandapplicationanalysisofdroughtmonitoringusingremotesensingWANGLitao1,WANGShixin1,ZHOUYi1,WANGFutao1,2,LIUWenliang1,21.InstituteofRemoteSensingApplications,ChineseAcademyofSciences,Beijing100101,China;2.GraduateUniversityofChineseAcademyofSciences,Beijing100039,ChinaAbstract:Remotesensingtechnologywiththecharacteristicsofrapid,economicalandmacroscopicprovidesanimportantreal-timedynamicdatasourcefordroughtmonitoringanddecisionmaking.Inthispaper,monitoringmethodsbasedonremotesensingdataareoverviewedandclassifiedintofourkinds:soilthermalinertiamethods,soilspectrumcharacteristicmethods,evapotranspirationmodelmethodsandvegetationindexmethods.Themonitoringprinciple,applicabilityandadvancesforeachmethodarepresented.CombinationwiththedroughtofSouthwestChinaoccurredinthespringof2010,adroughtremotesens-ingmethodusingvegetationwaterindicesisintroducedincludingmonitoringmodel,dataprocessingandapplicationanalysis.Andthemonitoringresultsarestatisticalanalyzedandevaluated.Keywords:droughtmonitoring,remotesensing,advances,applicationanalysisCLCnumber:TP79Documentcode:ACitationformat:WangLT,WangSX,ZhouY,WangFTandLiuWL.2011.Advancesandapplicationanalysisofdroughtmonitoringusingremotesensing.JournalofRemoteSensing,15(6):1315–13301316JournalofRemoteSensing遥感学报2011,15(6)methods,soilspectrumcharacteristicmethods,evapotranspirationmodelmethodsandvegetationindexmethods.2.1SoilthermalinertiamethodsSoilthermalinertia(STI)isathermalpropertythatsoilpreventsthechangingofitstemperature.STIhasagoodrelationshipwithsoilwatercontent.STIcanbeexpressedasbelow:(1)wherePissoilthermalinertia,λisthethermalconductivity,ρissoildensity,andcisthespecificheat.Becausethereisabigdif-ferencebetweentheheatcapacityandthermalconductivityofthedriedsoilandthoseofthewater,thesoilwithdifferentmoisturewillhavedifferentsoilthermalinertia(Price,1985).Thedroughtmonitoringresearchesusingsoilthermalinertiacanbesummarizedintothetwosteps.Atfirst,combinethegroundmodelwithremotesensingthermalinfrareddatatoconstructasoilthermalinertiamodelandcalculatethesoilthermalinertia.Then,establishthere-lation