简介:AcomparativestudyontheverticaldistributionsofaerosolopticalpropertiesduringhazeandfloatingdustweatherinShanghaiwasconductedbasedonthedataobtainedfromamicropulselidar.Therewasadistinctdifferenceinlayerthicknessandextinctioncoefficientunderthetwotypesofweatherconditions.Aerosolswereconcentratedbelow1kmandtheaerosolextinctioncoefficientsrangedfrom0.25to1.50km-1onhazedays.Incontrast,aerosolswithsmallerextinctioncoefficients(0.200.35km-1)accumulatedmainlyfromthesurfaceto2kmonfloatingdustdays.Theseasonalvariationsofextinctionandaerosolopticaldepth(AOD)forbothhazeandfloatingdustcasesweresimilargreatestinwinter,smallerinspring,andsmallestinautumn.Morethan85%oftheaerosolsappearedintheatmospherebelow1kmduringseverehazeandfloatingdustweather.Thediurnalvariationoftheextinctioncoefficientofhazeexhibitedabimodalshapewithtwopeaksinthemorningoratnoon,andatnightfall,respectively.Theaerosolextinctioncoefficientgraduallyincreasedthroughoutthedayduringfloatingdustweather.Casestudiesshowedthathazeaerosolsweregeneratedfromthesurfaceandthenliftedup,butfloatingdustaerosolsweretransportedverticallyfromhigheraltitudetothesurface.TheAODduringfloatingdustweatherwashigherthanthatduringhaze.Theboundarylayerwasmorestableduringhazethanduringfloatingdustweather.