Thetransportandchemicalproductionprocessesofnitrate,sulfate,andammoniumaerosolsoverEastAsiawereinvestigatedbyuseoftheModels-3CommunityMulti-scaleAirQuality(CMAQ)modelingsystemcoupledwiththeRegionalAtmosphericModelingSystem(RAMS).Fortheevaluationofthemodel'sabilityindepictingtheir3-dimensionalconcentrationdistributionsandtemporalvariations,modeledconcentrationsofnitrate,sulfate,andammoniumaerosolsarecomparedwiththeobservationsobtainedatagroundstationinJapaninMarch2001andonboardofanaircraftDC-8on18and21March2001duringtheTransportandChemicalEvolutionoverthePacific(TRACE-P)fieldcampaign.Comparisonshowsthatsimulatedvaluesofnitrate,sulfate,andammoniumaerosolsaregenerallyingoodagreementwiththeirobserveddata,andthemodelcapturesmostimportantobservedfeatures,andreproducestemporalandspatialvariationsofnitrate,sulfate,andammoniumaerosolconcentrationsreasonablywell,e.g.,thetimingandlocationsoftheconcentrationspikesofnitrate,sulfate,andammoniumaerosolsarewellreproduced,butlargediscrepanciesbetweenobservedandsimulatedvaluesarealsoclearlyseenatsomepointsandsometimesduetothecoarsegridresolutionanduncertaintiesoftheemissionsusedinthisstudy.ThiscomparisonresultsindicatethatCMAQisabletosimulatethedistributionsofnitrate,sulfate,andammoniumaerosolsandtheirrelatedspeciesinthetroposphereoverEastAsiareasonablywell.
