简介：Spatio-temporalvariationofactualevapotranspiration(ETa)inthePearlRiverbasinfrom1961to2010areanalyzedbasedondailydatafrom60nationalobservedstations.ETaiscalculatedbytheAdvection-Ariditymodel(AAmodel)inthecurrentstudy,andMann-Kendalltest(MK)andInverseDistanceWeightedinterpolationmethod(IDW)wereappliedtodetectthetrendsandspatialvariationpattern.TherelationsofETawithclimateparametersandradiation/dynamictermsareanalyzedbyPersoncorrelationmethod.Ourfindingsareshownasfollows:1)MeanannualETainthePearlRiverbasinisabout665.6mm/a.Ithassignificantlydecreasedin1961-2010atarateof-24.3mm/10a.Seasonally,negativetrendsofsummerandautumnETaarehigherthanthatofspringandwinter.2)ThevalueofETaishigherinthesoutheastcoastalareathaninthenorthwestregionofthePearlRiverbasin,whilethelatterhasshownthestrongestnegativetrend.3)NegativetrendsofETainthePearlRiverbasinaremostprobablyduetodecreasingradiationtermandincreasingdynamicterm.Thedecreaseoftheradiationtermisrelatedwithdecliningdiurnaltemperaturerangeandsunshineduration,andrisingatmosphericpressureaswell.Thecontributionofdynamictermcomesfromincreasingaveragetemperature,maximumandminimumtemperaturesinthebasin.Meanwhile,thedecreasingaveragewindspeedweakensdynamictermandfinally,toacertainextent,itslowsdownthenegativetrendoftheETa.