Theimpactsoftheenhancedmodel’smoistphysicsandhorizontalresolutionupontheQPFs(quantitativeprecipitationforecasts)areinvestigatedbyapplyingtheHIRLAM(highresolutionlimitedareamodel)tothesummerheavy-raincasesinChina.Theperformanceofthecontrolrun,forwhicha0.5°×0.5°gridspacingandatraditional“grid-boxsupersaturationremoval+Kuotypeconvectiveparamerization”areusedasthemoistphysics,iscomparedwiththatofthesensitivityrunswithanenhancedmodel’smoistphysics(Sundqvistscheme)andanincreasedhorizontalresolution(0.25°×0.25°),respectively.Theresultsshow:(1)Theenhancedmoistphysicsscheme(Sundqvistscheme),byintroducingthecloudwatercontentasanadditionalprognosticvariableandtakingintoaccountbrieflyofthemicrophysicsinvolvedinthecloud-rainconversion,doesbringimprovementsinthemodel’sQPFs.AlthoughthedeterioratedQPFsalsooccuroccasionally,theimprovementsarefoundinthemajorityofthecases,indicatingthegreatpotentialfortheimprovementofQPFsbyenhancingthemodel’smoistphysics.(2)Byincreasingthemodel’shorizontalresolutionfrom0.5°×0.5°,whichisalreadyquitehighcomparedwiththatoftheconventionalatmosphericsoundings,to0.25°×0.25°withoutthesimultaneousenhancementinmodelphysicsandobjectiveanalysis,theimprovementsinQPFsareverylimited.Withhigherresolution,althoughslightameliorationinlocatingtherainfallcentersandinresolvingsomefinerstructuresofprecipitationpatternaremade,thenumberofthemis-predictedfinestructuresinrainfallfieldincreaseswiththeenhancedmodelresolutionaswell.
