简介：Duetoincreasedaerosolemissionsandunfavorableweatherconditions,severehazeeventshaveoccurredfrequentlyinChinainthelast10years.Inaddition,theinteractionbetweentheboundarylayerandtheaerosolradiativeeffectmaybeanotherimportantfactorinhazeformation.Tobetterunderstandtheeffectofthisinteraction,theaerosolradiativeeffectonaseverehazeepisodethattookplaceinDecember2013wasinvestigatedbyusingtwoWRFChemmodelsimulationswithdifferentaerosolconfigurations.Theresultsshowedthatthemaximalreductionofregionalaveragesurfaceshortwaveradiation,latentheat,andsensibleheatduringthiseventwere88,12,and37Wm~(–2),respectively.Theplanetaryboundarylayerheight,daytimetemperature,andwindspeeddroppedby276m,1°C,and0.33ms~(–1),respectively.Theventilationcoefficientdroppedby8%–24%forinthecentralandnorthwesternYangtzeRiverDelta(YRD).Theupperleveloftheatmospherewaswarmedandthelowerlevelwascooled,whichstabilizedthestratification.Inaword,thedispersionabilityoftheatmospherewasweakenedduetotheaerosolradiativefeedback.AdditionalresultsshowedthatthePM_(2.5)concentrationinthecentralandnorthwesternYRDincreasedby6–18μgm~(–3),whichislessthan15%oftheaveragePM_(2.5)concentrationduringtheseverelypollutedperiodinthisarea.TheverticalprofileshowedthatthePM_(2.5)andPM_(10)concentrationsincreasedbelow950hPa,withamaximumincreaseof7and8μgm~(–3),respectively.Concentrationsreducedbetween950and800hPa,however,withamaximumreductionof3.5and4.5μgm~(–3),respectively.Generally,theaerosolradiativeeffectaggravatedthelevelofpollution,buttheeffectwaslimited,andthishazeeventwasmainlycausedbythestagnantmeteorologicalconditions.Theinteractionbetweentheboundarylayerandtheaerosolradiativeeffectmayhavebeenlessimportantthanthelarge-scalestaticweatherconditionsfortheformation

简介：Haze-to-fogtransformationduringalonglasting,lowvisibilityepisodewasexaminedusingtheobservationsfromacomprehensivefieldcampaignconductedinNanjing,Chinaduring4-9December2013.Inthisepisode,hazewastransformedintofogandthefoglastedfordozensofhours.Theimpactsofmeteorologicalfactorssuchaswind,temperature（T）andrelativehumidity（RH）onhaze,transitionandfogduringthisepisodewereinvestigated.Resultsrevealedsignificantdifferencesbetweenhazeandfogdays,duetotheirdifferentformationmechanisms.Comparisonwasmadeforboundary-layerconditionsduringhazydays,haze-to-fogdaysandfoggydays.DistributionsofwindspeedandwinddirectionaswellassynopticweatherconditionsaroundNanjinghaddeterminativeimpactsontheoccurrencesandcharacteristicsofhazeandfog.WeakenedsoutherlywindinsouthernNanjingresultedinhighconcentrationofpollutants,andhazeeventsoccurredfrequentlyduringthestudyperiod.Thewindspeedwaslessthan1ms-1inthehazeevent,whichresultedinastableatmosphericconditionandweakdispersionofthepollutants.Theheightofthetemperatureinversionwasabout400mduringtheperiod.Theinversionintensitywasweakandthetemperature-differencewas4℃km-1orlessinhaze,whiletheinversionwasstronger,andtemperature-differencewasabout6℃km-1,approachingtheinversionlayerintensityinthefogevent.HazeeventisstronglyinfluencedbyambientRH.RHvaluesincreased,whichresultedinhazedaysevidentlyincreased,suggestingthatanincreasingfractionofhazeeventsbecausedbyhygroscopicgrowthofaerosols,ratherthansimplybyhighaerosolloading.WhenRHwasabove90%,hazeaerosolsstartedtobetransformedfromhazetofog.Thisstudycallsformoreeffortstocontrolemissionstopreventhazeeventsintheregion.

简介：根据强壮的ENSO处理的1982/1983的比较，象快速的开发，巨大的紧张和突然的撤退那样的关键特征在1997/1998关于温暖的事件被揭示，为这个过程在它海洋和空气的发作和进化期间为热带印度洋和西方的太平洋管理intraseasonal摆动的特征特征地详细被学习。