取得学位：博士(理学)，学位授与番号：博甲第823号，学位授与年月日：平成18年3月22日,学位授与年：200

Yamada Maromu

山田, 丸

Kanazawa University Repository for Academic Resources

山田丸博士（理学）博甲第８２３号平成１８年３月２２曰課程博士（学位規則第４条第１項）AerosolmixingstatesoverKOSAsourceregions：Singleparticleanalysisoffreetroposphericparticlescollectedwithaballoon-bornesampleroverDunhuangChina（黄砂発生源地域上空のエアロゾル混合状態：中国敦煙にて気球搭載型サンプラーにより採集した自由対流圏粒子個々の分析）岩坂泰信（自然計測応用研究センター・教授）早川和一（自然科学研究科・教授），大谷吉生（自然科学研究科・教授），柏谷健二（自然計測応用研究センター・教授），～佐藤努（自然計測応用研究センター・助教授）氏名学位の種類学位記Ⅶ番号学位授与の日付学位授与の要件学位授与の題目論文審査委員(主査）論文審査委員|副査）Abstract：FreetroposphericparticlesWerecollectedusmgaballOon-bomeaerosolsampleronAugust29,Ｚ００２ａｎｄＭａｒｃｈ２４,Z003atDunhuang(40.00,Ｎ,94.30,E）mnorthwesternChina,mordertomvestigatethemixingstatesofaerosolparticlesoverKOSAsourceregions・TT1emorphologD/andelememalcompositionofthemdividualparticleswereanalyzedwithascanningelectronmicroscopeandanenergydispersiveX-rayanalyzer，Thesingle-particleanalysisrevealedthatmmeraldustparticleswerema]orconstimentsmcoarsemoderange(｡>11ｍ),andsulfateparticleswerepredommantlypresentmfinemoderange(0.2<d<１１L､)mtlle丘eetroposphereovertheTaklamakanDesertbothinspnngandmsunⅡner、However,theelementalcompositionoftheindividualdustparticlessignificantlydifferedbetweentheresuhsofAugust2002andMarch2003．Si-richparticlesweredominantmmineraldustonMarch2003，Ontheotherhand,evaporiteparticlessuchasCa-andNa-richdustparticlestoodoutattheresultsofAugust2002，althoughSi-richparticleswereamamtypeofmineraldustasusuaLAdditionally,compansonoftheelementalcompositionsoftheparticlescollectedoverDunhuangwiththoseofparticlescollectedoverJapanstronglysuggeststhattheseparticlesweresignificantlymodifiedbysulfhrduringtheirlong-rangetransport．１．１ntlUductionAsiandustparticles(KOSAparticles,literallymean"yellowsand,，inJapanese)originatedinaridandsemi-aridregionsintheAsiancontinentarefi･equentlydispersedtoeastemChina,Koreapeninsula，Japan，theNortllPacificandeventoNorthAmerica・ACcordingtorecentmanyinvestigations,KOSAparticlesmakeimportantcontributiontoregionaland/orglobalclimateandenviromnent,ｂｅcausetheparticlescanscatterand/Orabsorbsolarradiation,actaschemicalreactionsiteandplayascloudcondensationnucleioricenucleiintheatmosphere・MoreovenithasbeenbelievedthatKOSAparticleswillfacilitateoceanicprimalyproductivities,scinceFecontainedinKOSAfaUintoocean・Therefbrethelong-rangetransporｔｏｆＫＯＳＡｐａｒｔｉｃｌｅｓａｎｄｃｈｅｍｉｃａｌａｎｄphysicalmodificationofKOSAparticlesduringtheirtransportbecomemattersofgreatconcemand-432-consequentlyvanousresearchcampaignshavebeenmadetoclarifyenvironmentaIandclimateeffectsofKＯＳＡ・HoweventherehavebeenveryfewobservationsfbrbehaviorofaerosolparticlesinthefTeetroposphereOverKOSAsourceareasowmgtotechnicaldifficulties・WetherefbrehavestronglydesiredobservationsofthechemicalandphysicalpropertiesfbrfreetroposphericparticlesandtheparticlenumbeI七sizedistributioninthefreetroposphereoverthesourceareas．2．OlDservationandanalysisKnowledgeaboutaerosolmixturestatesintheffeetroposphereoverKOSAsourceregionsisessentialtoassesstheimpactonenvironmentchangecausｅｄｂｙＫＯＳＡ,becauseKOSAparticlestravellongdistancemainlythroughthefTeetropospheraForthatreason，ｗｅdevelopedtheballoon-bomesamplertocollectffeetroposphericparticles,andwedesiredseveraladvantagepointstothesamplenThatis（１）weightsavingtoallowlaunchingthesamplerbyrubberballoon,(2)cuttingofrtheropebetweenballooｎａｎｄｓａｍｐＩｅｒｂｙｔｈｅｒｏｐｅｃｕｔｔｅｒａｆｔｅrfinishingtlleparticlecollection,ａｎｄ（３）recovelyofthesampleonthebasisofGPSsignaLFigUrelshowstheballoon-trainfbrparticlecollectionintllefTeetroposphereandtheblockdiagramoftheballoon-bomeaerosolsampleH(b）４月1ｍ「《Ｏｌｌｅ、Ⅵ剛皿Ⅱ■ロロ［Ⅱ■n冊《⑥ｎｅＥ１2stage甑．（→．…→鐵FigureL(a)BalloOn-trainfbrparticlecollectionintheffeetroposphere,and(b)blockdiagraInoftheballoon-borneaerosolsamplen』-433-ＴWemadeelectronmicroscOpicanalysisofthefreetroposphericparticlesoverDunhuang，Chma(40゜00,Ｎ,94.30,E),whichislocatedmtheeastempartoftheTaklamakanDesertandhasbeensuggestedtobeanimportantsourceofKOSAparticles､TheirparticleswerecollectedinthethreedifTerentlayers-3-5km,５－７ｋｍ,ａｎｄ７－９ｋｍａｂｏＶｅｓｅａｌｅｖｅｌ－ｗｉｔｈａｂａｌloonborneaerosolsamplerequippedthreelow-volumeimpactOronAugust29,Z002andonMarch24,2003(Table.I)．Therecovelysystemwolkedvelywellatthattime,ａｎｄittookonlyseveralhourstorecoverthesamplesafterlandinglwhichseemstoavoidthecontaminationffomsurroundingairJThedistancebetweenballoonlaunchingandlandingpositionswasaboutl2kmonAugUst2002,ａｎｄ４８ｋｍｏｎＭａｒｃｈ２００，Thiskindofmeasurementisvelyeffectivetoknowthemixingstateoffieetroposphericaerosolsandwillbeargoodrippleeffectintheatmosphericsciencefield,altlloughthehandlingneedthetechnicalskill．Table１．．Samplingtimeandweatherconditions．Ｄate ＩＹｍｅ(ＧＭT）AUtimde（a.s､1.）SamplingtimeＷｉｎｄ weatherDireCtiOnSpeed(in/』3:31:12-3:37:123.2-5.2ｋｍ６ｍｉｎＮＮＥ－ＷＮＷ ５29-Aug-O2３:37:12-3:42:275.2-6.9ｋｍ５．２５ｍｉｎＮＷ Fｍｅ9.23:42:27-3:45:276.9-8.0ｋｍ３ｍｉｎＮＮＷ－ＷＮＷ１４．３1:52:07-2:00:5２３－５ｋｍ７．７５ｍｍ Ｗ 11.624-Mar-O3２:00:52-2:07:0７５－７ｋｍａ２５ｍｉｎＷＮＷ￣Ｗ Fine16.82:07:07-2:１３:３７ ７－９ｋｍ６．５ｍｉｎＷＮＷ－￣－＿1８．６Theparticlescollectedontocarbon-coatedcollodionfilmss叩portedbynickelgrids,ｗｈｉｃｈｗｅｒｅｓｅｔｏｎｅａｃｈｓｔａｇｅｏｆｔｈｅｌｏwvolumeimpactors，wereanalyzedwithascanningelectronmicroscopeandanenergydispersiveX-rayanalyzeLinordertoseetheparticlemorpholo部size，andelementalcomposition・ThediameterofeachparticlewascalculatedasthearithmeticmeanofthelongestwidthanditswidthorthogonaLWesimultaneouslyperfbrmedballoon-borneOPC(OpticalParticleCounteDmeasulements，aerosolparticlecollectionnearthesurfaceatmosphere,andlidarmeasurementsinDunhuan9,china．3．Ｒｅｓｕｌｔａｎｄｓｕｍｍｍｙ３､LExistenceofmineraldustparticlesbothinthespringandthesummerf丁eetroposphereElectronmicroscopicexperimentsrevealedtllatmostofthecoarseparticlescollectedintheffeetroposphereoverDunhuanｇｉｎｓｐｎｎｇａｎｄｅｖｅｎｍｓｕｎｎｅｒｃｏｍｐｏｓｅｄofmmeraldustparticles・ＦｉgUre2showstherepresentativemineraldustparticlescollectedusingtlleballoon-bornesampler、IY1eobservationsuggestSthatdustparticlesconstantlyexistinthefieetroposphereoverDunhuang,althoughthenumberconcentrationsarehigherinspringthaninsummer6Balloon-borneOPCandlidarmeasurementsalSosuggestedtheexistenceofdustparticlesinthefiPeetropospherenotonlyinspringbutalsoinsummenMineraltypesoftheindividualparticlescoUectedinthelowerffeetroposphereshowedasignificantdifferenceconsidemblybetweenthccasesofspringandthesummer・ＴｈecomparisonwiththepreviousresultsandthemeteorologicaldatasuggestedthattheaerosolparticlescollectedoverDunhuang-434-onMarch22,Z003exhibitedthemixingstateofaerosolparticlesunderduslyconditionOntheotherhand，theparticlescollectedonAugJlst２９，２００２showedrelativelyhighnumberfiactionsofCa-andNa-richparticles,whichareconsideredtobeevaporite・ItseemsthattherelativeabundancｅｏｆＣａ－andNa-richparticlesincreaseswhenthemineraldustconcentrationiｓｌｏｗ６3.2. TheTaklamakanDesertasapossiblesourceofbackgroundKOSAobservedoverJapanMineraldustparticleswerepredominantlyexistedincoarsｅｍｏｄｅｒａｎｇｅｉｎｔｈｅｆＴｅｅ(日）の］こコロロ易、」し〈0１２３４５６７Ｂ丼rayemissiDn(keV）(b）の］こコロロ湯口」凸〈 lトーーーーヨ０１２３４５６７８片rayemissiDn(keV）Figure2Scanningelectronmicroscopicimages(lefDandX-rayspectra(right)onrepresentativemineraldustparticlescollectedinthefreetroposphereoverDunhuang・Theparticlesof(a)and(b）areexamplesofaluminosilicate,andcalcite(CaCO3)COntainingalittlealuminosilicate．troposphereoverDunhuanginsumnenAccordingtoairmassfbrwardtrajectories,theairmassesobservedinthesunⅡnerpassedoverJapan(Figure3)．ItcanbesuggestedthattheTaklamakanDesertisapossiblesourceregionofKOSAparticleswhichdiffUsetodownwindareassuchasJapanislandsthroughtheffeetroposphereeveninsummerseasons、TheresultscouldsupportthepreviousresearchthatdiscUssedbackgroundKOSAonthebasisofaircraftbornemeasurementsmadeoverJapa､．3.3．MixingstateofthefineparticlesovertheKOSAsourcearea：Weclassifiedthefineaerosolparticles(0.2＜ｄ＜１．０１１ｍ)collectedinthefiPeetroposphereoverDunhuangintofburtypes(sulfateparticles,biomassbumingparticles,mineraldustparticles，heavymetalparticles)，accordingtodetectedelementsandsize、Figure3showsNumberfractionsofparticletypesineachaltimdeonMarch24,2003andonAugust29,2002．Inthefree-435-troposphere,sulfUrparticlesweremainparticlesinfinemoderanges(0.2<d<LO1un)．Inparticularthistendencywasmoresignificantindiameterrangeof0.2-0.31｣ｍ，andthedominantnumberffactionsofsulfilrparticlescouldbeindependentonatmosphericcondition・Ontheotherhand,thenumberffactionsofsulfUrparticlesindiameterrangeof0.3-1.0}unshowedlalgevariationineachsample・htllissizerange,themixingstateofaerosolsisafTectedrelativelystrongbydustparticles・Balloon-borneOPCmeasurementsalsosupportedtheaboveresults、BesidessulfiJrparticlesandmineraldustparticles,wealsofbundtheparticlesderivedｆｍｍｂｉｏｍａｓｓｂｕｍｉｎｇａｎｄｈｅａｖｙmetalparticlesinfinemoderangeintheffeetroposphereoverDunhuang．2003/3/2４ 0.3-1.011ｍ 2003/3/2４ 0.2〒0311ｍ7hｇｋｍ 7と９ｋｍ5.7ｋｍ 5-7kｍ3.51Kｍ 3.5ｋｍ096２０％ ４０９６６０９６Number丘action0.3-1.01｣､809610096 096２０％ ４０９６７．５０％Number日泪ctionO2-0.31u、8096100962002/8/2９ 2002/8/2９7.8ｍ、 7.8ｍ、５－７ｋｍ ５－７ｋｍ■■■■3-5ｍ、■■■■■■■■3-5ｋｍ0％２０％４０９６６０９６８０９６10096NUmberfaption0％２０％４０％６０％８０％100％NUmberfaction鬮Typcl■TypeⅡ□Type、Figure3・NumberfiPactionsofparticletypesineachaltitudeonMarch24,Z003andonAugust29,2002．Eachtypearerepresentsulfhteparticle(Typel),particlederivedfmmbiomassbur､ing(Typell),andmmeraldustparticle(TypellI)．3.4．ModificationofKOSAparticlesbysulfilrFigure4showstherelativeweightratiosofAl,Ｓ,andCafbrtheindividualmineralparticlesofsixcases・ThedashedlineinthescattelLplotshowstheweightratioofS/Cafbrgypsum(CaSO4H20)(=0.8)．Iftherearemanypointsplottedtotherightofthedashedline,itcanbeassumedthatconsiderableuptakeofSOxonmineralparticleshardlyoccurs、MostofthedustparticlescollectedintheffeetroposphereandinthesurfaceatmosphereinDunhuang,ftomrelativeweightratiosofStoＣａｉｎFig.4.11,indicatedtllevalueoflowerthan0.8．ThemineraldustparticlescollectedinthefreetroposphereoverKOSAsOurceregionsstronglysuggestthat-436-significantuptakeofSOxbydustparticleshardlyOcculTed・A1sothemineraldustparticlesinthesurfaceatmosphereinDunhuangdidnotrelatewithsulfilrnotonlyduringduststormbutalsononduststoml・IncontrastabouthalfofdustparticlescollectedintheffeetroposphereoverJaPanwasseemedtobedustparticlessignificantlymodifiedbysulfULThefactisofconsiderableinterestwhendiscussmgthemodificationdUringtheirlong-rangetransportation・TheresultssuggestthattheSignificantmodificationofKOSAparticleshavenotocculTedatleastinaninitialstageoftheirlong-rangetransport,andwillbeoccurinthehumidairalongwithhighconcentrationofsulfUrdioxide．ｂ釦 ＣAＩ AＩ ＡＩＩ「ｌ「ⅡｒⅡＣａ Ｃａ CａdspringAIroverJaParAIｅｓｕｍｍｅｒ ＡＩ（Ｃ Ｃａ ＣａFigure4RelativeweightratiosofA1,sandCafOrmineralparticlescollected(a)３－５kmabovesealeveloverDunhuangonMarch24,2003,(b)S-7kmabovesealeveloverDunhuangonMarch24,2003,(c)３－５kmabovesealeveloverDunhuangonAugust29,(c)nearthesurfaceatmosphereatDunhuangonApril29,2002,（e)nearthesurfaceatmosphereatDunhuang,ａｎｄ(f）intheffeetroposphereoverJapan．-437-学位論文審査結果の要旨平成１８年１月２６曰の第１回審査委員会で予備的な審査を行い審査方針を決定したｂ同年２月２曰に最終発表を行い、引き続き第２回審査委員会を開いて以下の結論を得た。本論文は、タクラマカン砂漠上空（自由大気圏高度）の大気エアロゾルの混合状態を明らかにし、それに基づき「黄砂粒子への硫黄化合物の沈着が長距離輸送途中で生じている」こと、及び「タクラマカン砂漠がバックグランド黄砂の有力な発生源である」ことを示した。地球環境問題が社会的にも学問的にも大きな関心事となって以来、黄砂の変質過程の解明、東アジア西太平洋域での硫黄や窒素の生物地球化学的循環の解明、地球温暖化予測の精度向上などのために、「黄砂発生源の上空における黄砂粒子の混合状態」に関する知見は必須のものとみなされてきた。しかし、黄砂発生源地域の上空での観測は、技術的難度が高く、長い間、実証的研究が皆無であった。申請者は、気球搭載型の大気エアロゾル採集装置を開発（気球切り離し装置部分を担当）し、その成果をもとに中国の敦煙などで現地観測を行った。現地の自由大気圏で採集した試料の分析に基づく上記の結果は、関係分野で長い間待たれていたものであり、気象学や大気環境学の発展に大きな貢献をした。したがって、論文は博士（理学）を授与するに充分値するものと認められた。-438-

黄砂発生源地域上空のエアロゾル混合状態 : 中国敦煌にて気球搭載型サンプラーにより採集した自由対流圏粒子個々の分析

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黄砂発生源地域上空のエアロゾル混合状態 : 中国敦煌にて気球搭載型サンプラーにより採集した自由対流圏粒子個々の分析

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