简介:Athree-dimensionalglobalchemistrytransportmodel(OSLOCTM2)isusedtoinvestigatetheimpactofsubsonicaircraftNOxemissiononNOzandozoneoverChinaintermsofayear2000scenarioofsubsonicaircraftNOxemission.TheresultsshowthatsubsonicaircraftNOxemissionsignificantlyaffectsnorthernChina,whichmakesNOxat250hPaincreasebyabout50pptvwiththehighestpercentageof60%inJanuary,andleadingtoanozoneincreaseof8ppbvwith5%relativechangeinApril.TheNOxincreaseismainlyattributedtothetransportprocess,butozoneincreaseisproducedbythechemicalprocess.TheNOxincreasesbylessthan10pptvbyvirtueofsubsonicaircraftNOxemissionoverChina,andozonechangeslessthan0.4ppbv.WhensubsonicaircraftNOxemissionoverChinaisdoubled,itsinfluenceisstillrelativelysmall.
简介:Cloudmicrophysicalpropertyretrievalsfromtheactivemicrowaveinstrumentonasatelliterequiretheclouddropletsizedistributionobtainedfromaircraftobservationsasaprioridataintheiterationprocedure.Thecloudlognormalsizedistributionsderivedfrom12flightsoverBeijing,China,in2008–09werecharacterizedtoevaluateandimproveregionalCloudSatcloudwatercontentretrievals.Wepresentthedistributionparametersofstratiformclouddroplet(diameter<500μmand<1500μm)anddiscusstheeffectoflargeparticlesondistributionparameterfitting.Basedonthreeretrievalschemeswithdifferentlognormalsizedistributionparameters,theverticaldistributionofcloudliquidandicewatercontentwerederivedandthencomparedwiththeaircraftobservations.Theresultsshowedthattheliquidwatercontent(LWC)retrievalsfromlargeparticlesizedistributionsweremoreconsistentwiththeverticaldistributionofcloudwatercontentprofilesderivedfrominsitudataon25September2006.WethenappliedtwoschemeswithdifferentaprioridataderivedfromflightdatatoCloudSatoverpassesinnorthernChinaduringApril–Octoberin2008and2009.TheCloudSatcloudwaterpath(CWP)retrievalswerecomparedwithModerateResolutionImagingSpectroradiometer(MODIS)liquidwaterpath(LWP)data.TheresultsindicatedthatconsideringaprioridataincludinglargeparticlesizeinformationcansignificantlyimprovetheconsistencybetweentheCloudSatCWPandMODISCWP.Theseresultsstronglysuggestthatitisnecessarytoconsiderparticleswithdiametersgreaterthan50μminCloudSatLWCretrievals.