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

-10

0Wet Season - NEE increase: 24 %

NE

E (µ

mol

m-2s-1

)

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!