Page 35 - 2022年第53卷第9期
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Irrigationsignalanalysisandirrigatedareaextractionbasedon
opticalandradarremotesensing :
AcasestudyofCiyouirrigationarea,LingshouCounty,NorthChinaPlain
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YANGYongmin ,GUTao,WUDi,LONGAihua,QIUJianxiu,LIUHongxin 1
(1.ChinaInstituteofWaterResourcesandHydropowerResearch,Beijing 100038,China;
2.ResearchCanteronFloodandDroughtDisasterReductionoftheMinistryofWaterResources,Beijing 100038,China;
3.ChinaIrrigationandDrainageDevelopmentCenter,Beijing 100054,China;
4.SchoolofGeographyandPlanning,SunYat - senUniversity,Guangzhou 510275,China)
Abstract:Currently,statisticalinvestigationisthemainapproachtoderiveirrigatedarea,withlimitedtimeliness
andaccuracy ,whiletheinformationonactualirrigatedareaalongsideitsspatialdistributionanddynamicchanges
areurgentlydemandedinwatermanagementwithintheirrigatedarea.Inthisregard,anopticalandmicrowave -
basedmethodisproposedfordetectingirrigationsignalandextractingactualirrigatedarea.First ,simulationswere
performedusingwatercloudmodelcombinedwithin - situsoilmoisturemeasurementstoquantifythechangesin
backscattercoefficientsduetoirrigationevents.Then,usingbackscattercoefficientsfromSentinel - 1withhighre
visitfrequency,amethodbasedontime - seriesdifferenceandlocalthresholdisproposed,andconductedforex
tractionofirrigatedareainCiyouirrigationareaofLingshouCounty ,NorthChinaPlain.Theresultsshowthatirri
gationeventsinspringwheatplotscanleadtofluctuationofradarbackscattercoefficientsinCbandbymorethan
1dB ,thusirrigationsignalscanbedetectedbyradarsatelliteswithanabsoluteaccuracysuperiorto1dB.Time -
seriesofradarbackscattercoefficientsanalysisindicatesthatduetoirrigationevents , significantincreaseof
C - bandradarbackscattercoefficientswillbefollowedbyobviousdecrease.Unlikeprecipitationevent ,localfea
turesareprominentinirrigation - inducedradarbackscattercoefficientsvariation.Throughfieldsurveysamplevali
dation ,theproposedmethodshowedoverallaccuracyof76.6% inextractingactualirrigatedarea.Theareasoffirst
canalirrigationduringthewheatseedlingestablishmentperiodandduringelongationperiodareabout92,000and
106,400acresrespectively.Inaddition,duetotheobvioustimedifferencebetweenwellirrigationareaandcanal
irrigationarea ,theirrigationareaofdifferentwatersourcescanbedetectedbasedonradarremotesensing,andthe
wellirrigationareainthestudyareaisabout39,000acres.Theproposedmethodcanprovidetechnicalsupportfor
applicationssuchasregionalirrigationareasurveysandbasinwaterresourcemanagement.
Keywords:irrigatedarea;radarremotesensing;backscattercoefficients;watercloudmodel
(责任编辑:耿庆斋)
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