Forest-atmosphere interac0on in tropical and boreal...
Transcript of Forest-atmosphere interac0on in tropical and boreal...
Forest-atmosphere interac0on in tropical and boreal ecosystems.
Review
EditorsHCHanssonandPauloArtaxo
Authors 1 JaanaBäck,Hans-ChristenHanssonandPauloArtaxo2 MariaAssunçãoFausdaSilvaDias,LuizAugustoMachado3 DanielRosenfeld4.1 SamaraCarbone,LiineHeikkinen,TuukkaPetäjä4.2 MariaPraß,ChristopherPöhlker,VivianeR.Després,BeVnaWeber,JaanaBäck4.3 LucianaRizzo,JianWang,FlorianDitas,PeterTunved,JostHeintzenberg 4.4 BrunaHolanda,LucianaRizzo,PaulZieger,AkiVirkkula4.5 PauloArtaxo,WilliamMorgan,GerritdeLeeuw,LarisaSogacheva,MarcoAuréliodeMenezesFranco.4.6 ErikSwietlicki,HCHansson,IlonaRiipinenGordonMcFiggan,HenriqueBarbosa,MiraPöhlker,RadovanKrejci,Ulrich
Pöschl4.7 AlexGuenther,JanneRinne,JaanaBäck,HanneleHakola4.8 JostLavric,JenniKontkanen,KatrianneLehbpalo,MarkkuKulmala4.9 JinshuChi,MadhiasPeichl,NilesHasselquistandMatsB.Nilsson,CelsoVonRandow4.10 HCHansson,PauloArtaxo5.1 AnaMariaYáñez-Serrano,EfstrabosBourtsoukidis,ElianeG.Alves,MadhiasSörgel5.2 Veli-MaVKerminen,JianWang,5.3 PhilipSber,LuizAugustoMachado6 AndiAndreae,EkaterinaEzhova,MarkkuKulmala,V-MKerminen,PauloArtaxo7 PauloArtaxoandHCHansson
Objec0ve
• Toputforwardandcomparehowtwomajorforesttypesinteractswiththeatmosphereandclimate.
• Weaimtoexplorehowtheseforestsecosystemsaffectandareaffectedbyatmosphericprocesses.
• Itisthe”natural”systemsandtheirinterac=onthatwewanttoexplore
Pallas
Hyybälä
ZOTTO
Theborealforestandimportantobservabonsites
Observa0ons; Atmospheric Chemistry
TimeseriesofPM1monthlyaveragedaerosolcomposiboninCentralAmazonia(ATTOtower),fromJanuary2014toDec2016.
Organicsdominatetheaerosolinboththeborealandtropicalforest
Seasonalandinterannualvariabonsintheaerosolparbculatemader(PM10)andTCMconcentrabons(a)andofdailyaveragedmeteorologicalparameters(b):temperature–redline;precipitabons–greylineandsymbols.
Meteorologyinboththeborealandtropicalforeststronglyaffecttheaerosol,concentrabonsandproperbes.
Amazonas Canada Russia
GroundbasedAODmeasurementsfromthreemajorforestedareas
Biomassburningaredominabngasourceinboththeborealandtropicalforestduringthesummeranddryperiods.
IncreaseinSOAformabonfrombackgroundtopollutedcondibonsforthewet(ler)anddry(right)seasonsinCentralAmazonia.Inthewetseason(ler)pollutedcondibonsincreaseaerosolmassfrom1.2to3.3ug/m³.INthedryseason,aerosolconcentrabonsincreasedfrom9to12ug/m³.(Sáetal.,2018,2019)
UrbanemissionsboostnaturalatmosphericchemistryovertheAmazonas
Observa0ons; Atmospheric Chemistry
• Organicaerosolsdominatethenaturalaerosolinboththeborealandtropicalforests,70-85%
• Forestfiresdominabnginbothsystemsinthedryandsummerperiods.Theanthropogenicinfluencelargerinborealduringwinter.
• Urbanemissionsspeedupthegasphasechemistryandinduceformabonofnewparbcles
• However2-3bmeshigherconcentrabonsofSO2andBCintheborealarea.Probablyduetoanthropogenicemissions
Observa0ons: Aerosol Size Distribu0on, Tropical
MedianparbclenumbersizedistribubonsataforestsiteinCentralAmazoniabetween2008and2014duringthe(a)wetand(b)dryseason.MeasurementsweretakenunderlowRHcondibons(30-40%)andabout10mabovethecanopy.Shadowsrepresentthe25-75thpercenblerange.ReproducedfromRizzoetal.,2018.
Airborneobservabonsofsubmicro-meterparbclesizedistribubonsatfivedifferentalbtudesaboveaforestareainAmazoniaon7March2014.ReproducedfromWangetal.,2016.
Observa0ons: Aerosol Size Distribu0on, Boreal
Seasonalmedianand25th-75thpercenblerangesofparbclenumbersizedistribubonsobservedatHyybäläandZOTTO2006-2011.MAM:March-May;JJA:June-August;SON:September-October;DJF:December-February.
NPFatHyybäläisdetectedincleanairmassesfromtheArcbcSeaorveryNorthAtlanbc.TheaerosolissampledintheforestcanopyZodoislocated1500kmfromtheSiberianCoastinthecentralSiberiaandthesamplingatZOTTOisat320meteralbtude.
Observa0ons: Aerosol Size distribu0on
• Theborealsites,HyybäläandZOTTO,donotagreeinconcentrabonandsizedistribubon.
• ATTOandZOTTOagreebeder.ComparingATTOdrywithZOTTOspringandsummershowsimilaragedsizedistribubons,probablystronglyaffectedbybiomassburning.WhileATTOwetandZOTTOfallandwintershowsignsofcloudprocessed.
• LackingNPFatZOTTOraisequesbonswhysostrongNPFoverFennoscandiaandnotNPF.Possiblyinfluenceofairpollubonormarineair?
Observa0ons: Aerosol Op0cal
Proper0es
Seasonalvariabonsofσsp, σapandSSAattheborealforestsitesHyybälä,PallasandZOTTOandATTO.Allσspareatλ=550nm,atHyybäläandPallasalsoσapandSSAareatλ=550nm.AtZodoσapandSSAareatλ=574nmandatATTOσapandSSAareatλ=637nm
Scad
ering
Absorpbo
m
Singlesc
aderingalbe
do
Hyybälä
Observa0ons: Aerosol Op0cal Proper0es
• TheAmazonianwet-seasonaveragesofbothscaderingandabsorpboncoefficientsarecloseZOTTOaverages.TheAmazoniandry-seasonaveragesarehigherthanwinteraveragesofpollutedairmassesattheborealsites.
• Thedry-seasonSSAaverageattheAmazoniansiteisatthesamelevelasthewinter-seasonaveragesatallborealsitesandthewet-seasonaverageatthesamelevelasthesummer-seasonaveragesattheborealsites.
• HyybälähaveashighvaluesaspollutedZOTTO.IsthebackgroundthesameorisHyybäläpollutedmostofthebme??
Amazonas Canada Russia
GroundbasedAODmeasurementsfromthreemajorforestedareas
Observa0ons: AOD and radia0ve effects
Observa0ons: AOD and radia0ve effects
0.0 0.2 0.4 0.6 0.8 1.0
-30
-20
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0Wet Season - NEE increase: 24 %
NE
E (µ
mol
m-2s-1
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Relative Irradiance
Dry Season - NEE increase: 46 %
Amazonia Rondonia Forest site 2000-2001
EffectsofaerosolsoncarbonuptakeexpressedasNEEfordryandwetseasonsinaLBAtowerinRondonia(RebioJaru),Amazonas.(Cirinoetal.,2014)
Observa0ons: AOD and direct radia0ve forcing • AODbmeseriesforCanadianandSiberiaborealforestsaswellasAmazonia,showbiomassburningisamajordrivingforceonaerosolconcentrabons,andradiabveforcingmodificabonovertheseforestecosystems.
• Biomassburningseasonvarieswithmeteorologicalcondibons.• Radiabonscaderinghasimportanteffectsontheradiabonbalanceintropicalforests,butplayaminorroleinboreal,duetodifferentlightintensity,diffusetodirectradiabonandleafareaindexcausingenhancementsinNEEof30%intropicalforestsand10%overboreal.
Observa0ons: Hygroscopic proper0es
Relabonshipbetweenparbcledrydiameterandκforborealandtropicalforests.Panelshowsthecomparisonamongsites.Themedianvaluesareshownwitherrorbarsbeing25thand75thpercenbles.Legendentriesalsoindicatetheslopeofthelinearregressiony=ax+bfit.FigurefromParamonovetal.,2013.
Dryparbclesize
Hyybälä
ATTO
Observa0ons: Hygroscopic proper0es Relabonshipofthecomposibon-derivedhygroscopicityparameterκtothebinnedandaveragedrabooforganic(OA)toinorganic(IA)aerosolcomponents(Schmaleetal.,2018)for:FIK=Finokalia,Crete;MHD=MaceHead,Ireland;ATT=ATTOtower,Amazon;MEL=Melpitz,Germany;SMR=Hyybälä,Finland;JFJ=Jungfraujoch,Switzerland.Notethattheasymptobc-likeapproachofthecurvestowards0.1isduetotheassumpbonofκOA=0.1.
Observa0ons: Hygroscopic proper0es
• Hygroscopicproperbesarestronglydependantonthechemicalcomposibonbutarealsoinfluencedbysize.Typically,inorganiccompoundsarestronglyhygroscopicwhileorganicsaremuchlesshygroscopic.
• TheorganicsinAmazonismainlyisoprenedrivengivingSOAthatinlaboratorystudiesisfoundtobeslightlymorehygroscopicthantheborealmonoterpenedrivenSOA.Howeverobservabonsshowborealaerosoltobemorehygroscopic.
• Eventhoughsuchsmalldifferencescanhaveasignificanteffectontheradiabonbalance.Atleastinpresentmodels.
• EFFECTonCCN??????Mainlythedegreeofinorganics.
Observa0ons: BVOC emission
• TheBVOCemissionsarehighlysensibvetolandusechange,climatechange,andotherdisturbancesbutourlimitedunderstandingoftheprocessescontrollingthespecificresponsesmakesitdifficulttoquanbtabvelycompareandcontrasttropicalandborealecosystems.
• MajorandcleardifferenceisisopreneintheAmazonasandmonoterpenesintheborealforest.
• Theroleofthesedisturbancesindeterminingemissionvariabonsshouldbeapriorityforfutureresearchefforts.
Observa0ons: Land atmosphere exchange of CO2, CH4 and H2O in the boreal forests
HistogramsofpublishedannualnetecosystemexchangesofCO2andCH4inborealforestsfrom1990to2015.
Observa0ons: Land atmosphere exchange of CO2, CH4 and H2O in the Amazon
AnnualNetEcosystemExchangeofcarbonmeasuredinAmazonfluxtowersatprisbneforests,intheperiod1999-2006,comparedtomeasuredrainfallanddrynessindex(D=Rn/λP).AdaptedfromVonRandowetal.,2013.
Observa0ons: Land atmosphere exchange of CO2, CH4 and H2O • NaturalundisturbedforestsaresinkforCO2dueinparttotheCO2ferblizaboneffect.
• ForestNEEisregulatedbyrainfall,andanychangesinthehydrologicalcycleaffectsCO2exchange.RecentincreaseinextremeeventsarereducingthenetfluxofCO2inAmazonia.
• TropicalforestsarethemajorsourceofN2O,duetohighnitrogenturnover.N2OandCH4areemidedbytropicalsoils,andincreaseinglobaltemperaturecanchangethesefluxes.
Observa0ons: Trace gas concentra0ons and emissions • Forestinteractsstronglywiththeatmosphere.IntermsofCO2forestsarekeytosequesteratmosphericCO2.MeteorologyaffectsCO2sequestrabon!
• TropicalfloodedareasareamajorsourceofCH4,aswellasborealregionswithpermafrost.
• COandO3precursorsfrombiomassburningarekeytoregulateoxidabveprocessesintheatmosphere.
• OzonedamagetoplantscanreducesignificantlytheCO2uptakefortropicalforests.OHreacbvityiscontrolledbyVOCemissionsandreacbons,andiskeytoatmosphericlifebmeofkeygases.
• NOXregulatesthepathwayofVOCsoxidabon.SO2emissionsareimportanttoNPFevenatverylowconcentrabons.
New Par0cle forma0on Schematic diagram showing processes producing fine particles as a result of convective cloud outflow above Suriname in Northern Amazonia, with enhanced ultrafine number concentrations at regions of cloud outflow, suggesting nucleation (Krejci et al., 2003). Martin et al, 2010, Reviews of Geophysics copies and says “TheoriginalintentwastodescribeobservabonsoverSuriname,buttheprocessesdepictedareapplicabletothewiderAmazonBasin.
New par0cle forma0on
• Outsidethewinterperiod,forma5onofnewaerosolpar5clesintheforestboundarylayerisafrequentphenomenonthroughoutthewesternEuropeanpartoftheborealforestzone,lessfrequentinthenorthernandSiberianpartsofthisregion,andapparentlyalmostnon-existentintheAmazonBasinandcentralSiberia.
• OvertheAmazon,free-troposphereNPFassociatedwithconvecbvecloudsystemsandsubsequententrainmentintotheboundarylayerappearstobeanimportantsourceofaerosolparbclesduringnon-pollutedperiods.
• ThemostplausiblereasonfortherareoccurrenceofNPFintheAmazonianandcentralSiberianboundarylayeristhelacknearbysulfursources,eventhoughtheavailablemixtureofbiogenicorganicvaporsmightalsoplayarole.
• OnceNPFistakingplace,thereappearstobeenoughorganicvaporsoverbothborealforestzoneandAmazoniatomakethenewly-formedparbclestogrowintosizesatwhichtheycaneffecbvelyinteractwiththeclimatesystem.
Ecosystem feedback processes
Aerosollifecycle,closeinteracbonecosystem-clouds Ecosystememissionaffectcloudsandradiabonaffecbngtheecosystem
AT LAST final conclusions • Theunderstandingofland-ecosystem-atmospherehasincreasedconsiderablylately,buts5llonaglobalscaletheknowledgeisonlyinmanypartsrudimentaryconcerningemissions,atmosphericchemistry,parbcleformabonandeffectoncloudandclimate.Thefeedbackprocessesaremostlyhypothebcalwheremanyinterferingprocessesarenotwellknown.
• Thecon5nentalandmostremoteborealforestseemsatthemomentleaststudiedandwheremajorecosystemchangesareexpectedtobelargeduetoclimatechange.
• Climatechange,temperatureandprecipita5onwillinducemajorchangesintheecosystemandwiththatintheinteracbonwiththeatmosphere.Knowledgeneeded!!!
• IwishforaCaTTO,TheCanadianTallTowerObservatory,placedasremoteaseverpossibleintheCanadianBorealForest.
Thankyouforyouradenbon!