Impact of Climate Change on the Monthly Runoff of a Semi-arid Catchment: Case Study Zarqa River Basin (Jordan)

[摘要] Inthispaper,thelong-termhydrologicalresponses(runoffandactualevapotranspiration)ofasemi-aridbasintoclimatechangeswereanalyzed.ThisbasinistheZarqaRiver(Jordan).Theclimatechangeswereimposedwithtwelvehypotheticalscenarios.Twoofthesescenarioswerebasedonthepredictionsofgeneralcirculationmodels(GCMs),namelytheHadleyandMPImodels.Theothertenscenariosareincrementalscenariosassociatedwithtemperatureincreasesby+2Cand+4Candchangesinprecipitationof0%,+10%,+20%,-10%,and–20%.Thesescenarioswereusedasabasisforobservingcausalrelationshipsamongrunoff,airtemperature,andprecipitation.TheSurface-Infiltration-Baseflow(SFB)waterbalancemodelthatwasdevelopedbyBoughton(1984)wasusedforobservingthesecausalrelationships.Firstly,arealprecipitationandpotentialevapotranspirationofthebasinareestimatedbasedontheobservedmeteorologicalandhydrologicaldata.ThemonthlyrunoffsimulationsarethenpredictedthroughtheapplicationoftheSFBmodel.Sevenyearsofmeteorologicalandhydrologicaldataareusedforcalibratingthemodel,andanotherSevenyearsoftherecordareusedformodelvalidation.TheglobaloptimizationtechniqueknownasShuffledComplexEvolution(SCE)methodisusedtoobtaintheoptimalparametersoftheSFBmodel.ThemodelperformedwellfortheZarqaRiverforwhichthecoefficientofdeterminationwas0.78.Theaveragemonthlyrunofffromthemodelcomparedwelltotheobservedaveragerunoff.Theerroroftheobservedandsimulatedstreamflowiswithinacceptancelimitandfoundtobearound18percent.Themodelperformanceinthevalidationstageisreasonableandcomparabletothoseofthecalibrationstage.Bothsetsofclimatechangescenariosresultedindecreasesinmonthlyrunoff.Differencesinhydrologicalresultsamongallclimatecasesareduetowiderangeofchangesinclimatevariables.

[学科分类] 生物科学（综合）

[关键词] Climate change;Optimization;Rainfall-runoff modeling;Incremental scenarios;Calibration;Validation