简介:Chemicalcomposition,hourlycounts,andsizesofatmosphericcarbonaceousparticlesweremeasuredtoinvestigatetheirmixingstateonclearandhazydays.623,122carbonaceousparticleswithsizes0.2-2.0μmwasanalyzedusingasingle-particleaerosolmassspectrometerfrom1stto17thJanuary2013.Particletypesincludedbiomass/biofuelburningparticles(biomass),elementcarbon(EC-dominant)particlesthatwerealsomixedwithbiomass/biofuelburningspecies(EC-biomass)orsecondaryspecies(EC-secondary),organiccarbon(OC),internallymixedOCandEC(OCEC),ammonium-containing(ammonium)andsodium-containing(sodium)particles.Oncleardaysthetoprankedcarbonaceousparticletypeswerebiomass(48.2%),EC-biomass(15.7%),OCEC(11.1%),andsodium(9.6%),whileonhazydaystheywerebiomass(37.3%),EC-biomass(17.6%),EC-secondary(16.6%),andsodium(12.7%).ThefractionsofEC-secondary,ammonium(10%),andsodiumparticletypeswereelevatedonhazydays.NumbersofEC-secondaryparticlesweremorethanfourtimesthoseoncleardays(4.1%).Thus,carbonaceousparticlesmixedwithammonium,nitrateandsulfateduringagingandtransport,enhancingtheirlightextinctioneffectsandhygroscopicgrowthunderhighrelativehumidityonhazydays,furtherreducingvisibility.Ourreal-timesingle-particledatashowedthatchangestomixingstatehadasignificantimpactonlightextinctionduringhazeeventsinNanjing.
简介:ThisstudyinvestigatesthecorrelationbetweenPM10andmeteorologicalfactorssuchaswindspeed,atmosphericvisibility,dewpoint,relativehumidity,andambienttemperatureduringabrownhazeepisode.InordertoidentifythepotentialsourcesofPM10duringbrownhazeepisode,respirableparticulatematter(PM10)wascollectedduringbothnon-hazedaysandhazedaysandfurtheranalyzedformetallicelements,ionicspecies,andcarbonaceouscontents.Amongthem,ionicspeciescontributed45-64%toPM10,whilemetallicelementscontributed7-21%toPM10whichwassmallerthantheotherchemicalconstituents.TheaverageOC/ECratio(42)inhazedayswasaboutthreetimesoftheaverageOC/ECratio(14)innon-hazedays.Byusingchemicalmassbalance(CMB)receptormodel,themajorsourceswereapportioned,includingtraffics,incinerators,coalcombustion,steelindustry,petrochemicalindustry,andsecondaryaerosols,etc.ThecontributiontoPM10concentrationofeachsourcewascalculatedforallthesamplescollected.TheresultsshowedthatcoalcombustionwasthemajorsourceofPM10innon-hazedaysandsecondaryaerosolswerethemajorsourceinhazedays,followedbypetrochemicalindustry,incinerators,andtraffics,whileothersourceshadnegligibleeffect.
简介:Regionaldroughtanalysisprovidesusefulinformationforsustainablewaterresourcesmanagement.Inthispaper,astandardizedprecipitationindex(SPI)atmultipletimescaleswasusedtoinvestigatethespatialpatternsandtrendsofdroughtintheHanRiverBasin,oneofthelargesttributariesofYangtzeRiver,China.Itwasfoundthat,intermsofdroughtseverity,theupperbasinoftheHanRiveristheleast,whilethegrowingtrendisthemostconspicuous;alessconspicuousgrowingtrendcanbeobservedinthemiddlebasin;andthereisaninsignificantdecreasingtrendinthelowerbasin.Meanwhile,theimpactofdroughtontheMiddleRouteoftheSouth-to-NorthWaterTransferProjectwasinvestigated,anditissuggestedthatwaterintakemustbereducedintimesofdrought,particularlywhensuccessiveorsimultaneousdroughtsintheupperandmiddlebasinsoftheHanRiverBasinoccur.TheresultscanprovidesubstantialinformationforfuturewaterallocationschemesoftheSouth-to-NorthWaterTransferProject.
简介:Theobjectiveofthisstudywastoobtainspatialdistributionmapsofpaddyricefieldsusingmulti-datemoderate-resolutionimagingspectroradiometer(MODIS)datainChina.Paddyricefieldswereextractedbyidentifyingtheuniquechar-acteristicofhighsoilmoistureinthefloodingandtransplantingperiodwithimprovedalgorithmsbasedonricegrowthcalendarregionalization.Thecharacteristiccouldbereflectedbytheenhancedvegetationindex(EVI)andthelandsurfacewaterindex(LSWI)derivedfromMODISsensordata.Algorithmsforsingle,early,andlatericeidentificationwereobtainedfromselectedtypicaltestsites.Thealgorithmscouldnotonlyseparateearlyriceandlatericeplantedinthesamefields,butalsoreducetheuncertainties.ThearealaccuracyoftheMODIS-derivedresultswasvalidatedbycomparisonwithagriculturalstatistics,andthespatialmatchingwasexaminedbyETM+(enhancedthematicmapperplus)imagesinatestregion.Majorfactorsthatmightcauseerrors,suchasthecoarsespatialresolutionandnoisesintheMODISdata,werediscussed.Althoughnotsuitableformonitoringtheinter-annualvariationsduetosomeinevitablefactors,theMODIS-derivedresultswereusefulforobtainingspatialdistributionmapsofpaddyriceonalargescale,andtheymightprovidereferenceforfurtherstudies.
简介:O.General;1.Physicalacoustics;2.Underwatersound;3.Mechanicalvibrationandshock;4.Noiseandnoisecontrol;5.Ultrasonics;6.Speechacousticsandspeechcommunication;7.Physiologicalacoustics;8.Ar-chitecturalacoustics;9.Electroacoustics;10.Acousticalmeasurementandinstrumentation;11.Atmosphericacoustics;12.Geoacoustics;13.Bioaoustics;14.Musicalacoustical;15.Signalprocessing.
简介:BasedonthenoisesurveyinChina,theformula(H′=H+N-HN/120)ofISO/DIS1999.2("Acous-tics-DeterminationofOccupationalnoiseexposureandestimationofnoise-inducedhearingimpairment,1985)wasappliedtothecalculationofthehearingthresholdlevelassociatedwithageandnoise(HTLAN)ofthenoise-impairedpeople.AccordingtotheGaussciandistribution,whenthenoise-exposurelevelLEX8hwas85,90,95,100dBandthehearingthresholdfrequencyisfrom0.5kto6kHz,theHTLANofnoise-exposedpeoplewithdifferentdurationofexposureanditsrelationvaluestothehearingthresholdfrequencyassociatedwithage(HTLA)wereobtained.TheISO/DIS1999.2hasbeenprovedtobeapplicableinChina.
简介:FromthecasestudyofEveningBellRingingatNanpingHill,oneoftheWestLakeCulturalLandscapesinHangzhou,China,weinvestigatedthesoundscapeofascenicareawithaprofoundculturalbackground.First,weconductedthesoundscapephysicalindexoftheareainbothwinterandspringseasonstoanalyzeitsobjectivegraphicalexpression.Second,wefocusedonpeople’sreactionstothesoundscapeinordertoobtainasubjectiveevaluationofeachcomponentinthesoundscapeandintegratedenvironment.Then,therelationshipbetweentheobjectivedataandthesubjectiveevaluationwasanalyzed.Finally,theimpactsofthenaturalenvironment,history,andculturalfactorsontheevaluationoftheJingciTemplesoundscapewerestudied.Itwasfoundthatnaturalsounds,culturalsounds,andhistoricsoundswerewidelyacclaimedinpeople’ssubjectivefeelings,whichindicatedthecloserelationshipsamonghistoricalandculturalbackground,soundscape,andnaturalenvironment.Thus,theconclusionwasmadethatsoundscapeshouldbeconsistentwiththelocalnaturalenvironmentandthehistoricalandculturalbackground.
简介:Naturalsurfacecoatingscollectedfromnaturalsubstances(NSCsNS)wereemployedtostudytherolesofthemainchemicalcomponents(ironoxides,manganeseoxides,andothercomponents)incontrollingtheadsorptionoflead(Pb)andcadmium(Cd)inaquaticenvironments.TheselectivechemicalextractionfollowedbytheadsorptionofPbandCdexperimentsandstatisticalanalysis,wereusedtoinvestigatetheadsorptionpropertyofeachcomponent.Hydroxylaminehydrochloridewasusedtoremovemanganeseoxidesselectively,andsodiumdithionitewasusedtoextractironoxidesandmanganeseoxides.TheresultindicatedthatironoxidesandmanganeseoxidesplayedanimportantroleintheadsorptionofPbandCdonNSCsNS,andtherelativecontributionwasabouttwo-thirds.Thecontributionofmanganeseoxideswasthegreatest,withalesserroleindicatedforothercomponents.TheadsorptionabilityofmanganeseoxidesforPbandCdwasgreaterthanthatofironoxidesorothercomponentsforPbandCd.ThePbadsorptionobservedineachcomponentwasgreaterthanCdadsorption.
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