Abstract:

Abstract:Flood/droughtisoneofthemostinfluentialclimaticdisastersinPoyangLakebasin．Intraditional
flood/droughtmonitoring,precipitationdatausedareusuallyfrom ground meteorologicalobservation
sites．However,duetotheheterogeneityofregionalprecipitationoverspaceandtime,quantityandspatial
distributionsofmeteorologicalstationsfrequentlylimittheoverallaccuracyoftheregionalflood/drought
analysis．AsonemajormeansofspaceＧbasedobservations,inrecentyears,satelliteremotesensinghasbeＧ
comeanincreasinglyimportanttechniqueforregionprecipitationchangemonitoring．Inthispaper,TRMM
(TropicalRainfallMeasuringMission)satellite３B４２precipitationdatainPoyangLakebasin,firstly,were
evaluatedandcomparedthroughthebiasofrainfallamountandoccurrencefrequencyunderdifferentrainＧ
fallintensity,andthenbeusedtoreflectthespatioＧtemporaldistributioncharacteristicsoffloods/droughts
bytheZindexmethodinPoyangLakebasinfromJanuary１９９８toDecember２０１０．TheirreliabilitywasalＧ
sovalidatedbythe１５raingaugestationsinthebasinusingthesamemethod．TheresultsshowedasfolＧ
lows．(１)TheoccurrencefrequencyandrainfallamountcontributionsofdailyTRMMprecipitationunder
differentrainfallintensityhadahighlevelofconsistencywithgroundgaugesobservation．Andatmonthly
scale,thehighcorrelationcoefficientbetweenobservedrainfalldataandTRMMgridprecipitationindicated
thattheTRMMprecipitationcouldcorrectlyreflecttherainfallinPoyangLakebasin．(２)ZindexcalculatＧ
edbyTRMM precipitationshowedanincreaseＧdecreasealternantvariationaround０between１９９８and
２０１０．Theirvariationprocessandtrendswereconsistentwiththeresultsoftworaingaugesdataandthe
correlationcoefficientswere０??８９６and０??９１４,respectively．(３)ThefloodeventsinPoyangLakebasinocＧ
curredmainlyfromApriltoJuneandaccountedforabout６０％,whichwasalsothemainwetseasonofPoyＧ
angLakebasin,andthedroughtoccurredmainlyfromSeptembertoJanuaryofthefollowingyear．And
theirdistributionpatternswereconsistentwiththeannualdistributioncharacteristicsofprecipitation．(４)
ThespatialdistributionofZindexandflood/droughtgradesbasedonTRMMprecipitationwasconsistent
withthedistributionofrainfallinApril,２０１０andNovember,２００７,whichrepresentedthewetanddry
monthrespectively．TRMM precipitationdatacanbeusedtoevaluatetheareaandseverityoffloodor
droughtinPoyangLakebasin．Abstract:Flood/droughtisoneofthemostinfluentialclimaticdisastersinPoyangLakebasin．Intraditional
flood/droughtmonitoring,precipitationdatausedareusuallyfrom ground meteorologicalobservation
sites．However,duetotheheterogeneityofregionalprecipitationoverspaceandtime,quantityandspatial
distributionsofmeteorologicalstationsfrequentlylimittheoverallaccuracyoftheregionalflood/drought
analysis．AsonemajormeansofspaceＧbasedobservations,inrecentyears,satelliteremotesensinghasbeＧ
comeanincreasinglyimportanttechniqueforregionprecipitationchangemonitoring．Inthispaper,TRMM
(TropicalRainfallMeasuringMission)satellite３B４２precipitationdatainPoyangLakebasin,firstly,were
evaluatedandcomparedthroughthebiasofrainfallamountandoccurrencefrequencyunderdifferentrainＧ
fallintensity,andthenbeusedtoreflectthespatioＧtemporaldistributioncharacteristicsoffloods/droughts
bytheZindexmethodinPoyangLakebasinfromJanuary１９９８toDecember２０１０．TheirreliabilitywasalＧ
sovalidatedbythe１５raingaugestationsinthebasinusingthesamemethod．TheresultsshowedasfolＧ
lows．(１)TheoccurrencefrequencyandrainfallamountcontributionsofdailyTRMMprecipitationunder
differentrainfallintensityhadahighlevelofconsistencywithgroundgaugesobservation．Andatmonthly
scale,thehighcorrelationcoefficientbetweenobservedrainfalldataandTRMMgridprecipitationindicated
thattheTRMMprecipitationcouldcorrectlyreflecttherainfallinPoyangLakebasin．(２)ZindexcalculatＧ
edbyTRMM precipitationshowedanincreaseＧdecreasealternantvariationaround０between１９９８and
２０１０．Theirvariationprocessandtrendswereconsistentwiththeresultsoftworaingaugesdataandthe
correlationcoefficientswere０??８９６and０??９１４,respectively．(３)ThefloodeventsinPoyangLakebasinocＧ
curredmainlyfromApriltoJuneandaccountedforabout６０％,whichwasalsothemainwetseasonofPoyＧ
angLakebasin,andthedroughtoccurredmainlyfromSeptembertoJanuaryofthefollowingyear．And
theirdistributionpatternswereconsistentwiththeannualdistributioncharacteristicsofprecipitation．(４)
ThespatialdistributionofZindexandflood/droughtgradesbasedonTRMMprecipitationwasconsistent
withthedistributionofrainfallinApril,２０１０andNovember,２００７,whichrepresentedthewetanddry
monthrespectively．TRMM precipitationdatacanbeusedtoevaluatetheareaandseverityoffloodor
droughtinPoyangLakebasin．