简介：Drylandsareamongthoseregionsmostsensitivetoclimateandenvironmentalchangesandhuman-inducedperturbations.Themostwidelyaccepteddefinitionofthetermdrylandisaratio,calledtheSurfaceWetnessIndex(SWI),ofannualprecipitationtopotentialevapotranspiration(PET)beingbelow0.65.PETiscommonlyestimatedusingtheThornthwaite(PETTh)andPenman–Monteithequations(PETPM).ThepresentstudycomparedspatiotemporalcharacteristicsofglobaldrylandsbasedontheSWIwithPETThandPETPM.ResultsshowedvastdifferencesbetweenPETThandPETPM;however,theSWIderivedfromthetwokindsofPETshowedbroadlysimilarcharacteristicsintheinterdecadalvariabilityofglobalandcontinentaldrylands,exceptinNorthAmerica,withhighcorrelationcoefficientsrangingfrom0.58to0.89.Itwasfoundthat,during1901–2014,globalhyper-aridandsemi-aridregionsexpanded,aridanddrysub-humidregionscontracted,anddrylandsunderwentinterdecadalfluctuation.Thiswasbecauseprecipitationvariationsmademajorcontributions,whereasPETchangescontributedtoamuchlesserdegree.However,distinctdifferencesintheinterdecadalvariabilityofsemi-aridanddrysub-humidregionswerefound.ThisindicatedthattheinfluenceofPETchangeswascomparabletothatofprecipitationvariationsintheglobaldry–wettransitionzone.Additionally,thecontributionofPETchangestothevariationsinglobalandcontinentaldrylandsgraduallyenhancedwithglobalwarming,andtheThornthwaitemethodwasfoundtobeincreasinglylessapplicableunderclimatechange.