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1、RSE-07764;NoofPages10RemoteSensingofEnvironmentxxx(2010)xxx–xxxContentslistsavailableatScienceDirectRemoteSensingofEnvironmentjournalhomepage:www.elsevier.com/locate/rseAssessingdroughtprobabilityforagriculturalareasinAfricawithcoarseresolutionremotesensingimageryaba,⁎
2、O.Rojas,A.Vrieling,F.RemboldaJointResearchCentre,EuropeanCommission,TP266,21027Ispra(VA),ItalybUniversityofTwente,FacultyofGeo-InformationScienceandEarthObservation,P.O.Box6,7500AAEnschede,TheNetherlandsarticleinfoabstractArticlehistory:Droughtisoneofthemostfrequentcli
3、mate-relateddisastersoccurringacrosslargeportionsoftheAfricanReceived29March2010continent,oftenwithdevastatingconsequencesforthefoodsecurityofagriculturalhouseholds.ThisstudyReceivedinrevisedform7September2010proposesanovelmethodforcalculatingtheempiricalprobabilityofh
4、avingasignificantproportionoftheAccepted18September2010totalagriculturalareaaffectedbydroughtatsub-nationallevel.First,weusedtheper-pixelVegetationHealthAvailableonlinexxxxIndex(VHI)fromtheAdvancedVeryHighResolutionRadiometer(AVHRR)averagedoverthecropseasonasmaindrought
5、indicator.AphenologicalmodelbasedonNDVIwasemployedfordefiningthestartofseasonKeywords:Agriculturaldrought(SOS)andendofthegrainfillingstage(GFS)dates.Second,theper-pixelaverageVHIwasaggregatedforRemotesensingagriculturalareasatsub-nationallevelinordertoobtainadroughtinten
6、sityindicator.SeasonalVHIaveragingNDVIaccordingtothephenologicalmodelprovedtobeavaliddroughtindicatorfortheAfricancontinent,andisAfricahighlycorrelatedwiththedroughteventsrecordedduringtheperiod(1981–2009).ThefinalresultsexpressDroughtprobabilitytheempiricalprobabilityo
7、fdroughtoccurrenceoverboththetemporalandthespatialdomain,representingapromisingtoolforfuturedroughtmonitoring.©2010ElsevierInc.Allrightsreserved.1.IntroductionDroughtriskcalculationatcontinentalscaleiscurrentlylimitedbythescarcityofreliablerainfalldata.Thecoverageofope
8、rationalDroughtscanhavedevastatingeffectsonwatersupply,cropweatherstationsinmostAfricancountriesshowslargespatialgaps
