ENVRIplus DELIVERABLE

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A document of ENVRIplus project - www.envri.eu/envriplus

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 654182

D4.1 Report on crosscutting issues,

associated existing monitoring capacit ies and selected open case studies result ing

from the Interdisciplinary workshop

WORKPACKAGE4–JointoperationsacrosstheResearchInfrastructuredomainsLEADINGBENEFICIARY:INRA

Author(s): Beneficiary/Institution

AbadChabbi,CathrineLundMyhre,GregoryStarr,HenryLoescher,NicholasMeskhidze,NicolasBellouin,SilvanoFares,WilfriedWiniwarter,

AbadChabbiINRA[ANAEE],KarineSelegeriCNRS[ACTRIS],Jean-DanielParisCEA[ICOS],VitoVitale+MauroMazzolaCNR[SIOS]MichaelCunliffeMBA[EMBRC],RichardLampittNERC/NOC,SylviePouliquenEURO-ARGO,MichaelMirtlEAA,CathrineLundMyhre(NILU)

Acceptedby:Jean-DanielParis(WP4leader

Deliverabletype:REPORT

Deliverableduedate:31.10.2016/M18

ActualDateofSubmission:31.10.2016/M18

Ref. Ares(2016)6209899 - 31/10/2016

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ABSTRACTTheworkshopaimstobuildbridgesacrossnetworksofobservatoriesandtodeterminehowemergingenvironmentalresearchquestionscanbenefitfromthesenewinteractions.Theworkshopidentifykeyinterdisciplinarychallengesacrosssubdomainsthatwewilladopt,promoteandimplementwithintheENVRIplus.Specialattentionwasgivenoncombiningdifferentnetworksofobservatories,focusingonafewcurrentscientificissuesforsocietalbenefit.

Projectinternalreviewer(s):

Projectinternalreviewer(s): Beneficiary/Institution

WernerLeoKutsch UniversityofHelsinki/ICOSHeadOfficePOBox4800014UniversityofHelsinkiFinland

Jean-DanielParis

ICOS-RAMCESLaboratoiredesSciencesduClimatetdel'Environnement,CEASaclay,OrmedesMerisiers91191GifsurYvette,France

Documenthistory:

Date Version

8.10.2016 Draftforcomments

27.10.2016

Correctedversion

31.10.2015

AcceptedbyWPJean-DanielParis(WPLeader)

DOCUMENTAMENDMENTPROCEDUREAmendments,commentsandsuggestionsshouldbesenttotheauthors(AbadChabbi,abad.chabbi@inra.fr)

TERMINOLOGYAcompleteprojectglossaryisprovidedonlinehere:https://envriplus.manageprojects.com/s/text-documents/LFCMXHHCwS5hh

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PROJECTSUMMARYENVRIplusisaHorizon2020projectbringingtogetherEnvironmentalandEarthSystemResearchInfrastructures,projectsandnetworkstogetherwithtechnicalspecialistpartnerstocreateamorecoherent,interdisciplinaryandinteroperableclusterofEnvironmentalResearchInfrastructuresacrossEurope.Itisdrivenbythreeoverarchinggoals:1)promotingcross-fertilizationbetweeninfrastructures,2)implementinginnovativeconceptsanddevicesacrossRIs,and3)facilitatingresearchandinnovationinthefieldofenvironmentforanincreasingnumberofusersoutsidetheRIs.

ENVRIplusalignsitsactivitiestoacorestrategicplanwheresharingmulti-disciplinaryexpertisewillbemosteffective.TheprojectaimstoimproveEarthobservationmonitoringsystemsandstrategies,includingactionstoimproveharmonizationandinnovation,andgeneratecommonsolutionstomanysharedinformationtechnologyanddatarelatedchallenges.ItalsoseekstoharmonizepoliciesforaccessandprovidestrategiesforknowledgetransferamongstRIs.ENVRIplusdevelopsguidelinestoenhancetransdisciplinaryuseofdataanddata-productssupportedbyapplieduse-casesinvolvingRIsfromdifferentdomains.Theprojectcoordinatesactionstoimprovecommunicationandcooperation,addressingEnvironmentalRIsatalllevels,frommanagementtoend-users,implementingRI-staffexchangeprograms,generatingmaterialforRIpersonnel,andproposingcommonstrategicdevelopmentsandactionsforenhancingservicestousersandevaluatingthesocio-economicimpacts.

ENVRIplusisexpectedtofacilitatestructurationandimprovequalityofservicesofferedbothwithinsingleRIsandatthepan-RIlevel.Itpromotesefficientandmulti-disciplinaryresearchofferingnewopportunitiestousers,newtoolstoRImanagersandnewcommunicationstrategiesforenvironmentalRIcommunities.Theresultingsolutions,servicesandotherprojectoutcomesaremadeavailabletoallenvironmentalRIinitiatives,thuscontributingtothedevelopmentofacoherentEuropeanRIecosystem.

TABLEOFCONTENTS

INTRODCUCTION..................................................................................................41. Nitrogen,fromagriculturalfieldstothecoastalocean:theconceptofnitrogenbudgetsandcorollaryresearchinfrastructurescontributions..............52. Phytoplanktonbloomsfromcoastaltoopenocean....................................62.1OceanicEmissions,MarineAerosolsandClouds.......................................62.2ObservationsforEarthSystemmodelling..................................................7

3. Arcticobservation,withspecialfocusonCH4.............................................94. SimulatingandmonitoringO3andCO2deposition/coupling/interaction 11CONCLUSIONS....................................................................................................12IMPACTONPROJECT......................................................................................12IMPACTONSTAKEHOLDERS...........................................................................12

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Reportoncrosscuttingissues,associatedexistingmonitoringcapacitiesandselectedopencasestudiesresultingfromtheInterdisciplinaryworkshopINTRODCUCTIONTheScienceAcrossObservatoryNetworksinternationalworkshopwasheldinZandvoort,

NetherlandsonMay9th,asparttheENVRIPlusWeek.TheworkshopwascoordinatedbyacommitteeincludingAbadChabbi,INRA,France;AriAsmi,U.Helsinki,FinlandandJean-DanielParis,CEA,France)andaScientificCommittee(included;AbadChabbi,INRA,France;HankLoescher,NEON,USA;GelsominaPappalardo,CNR,Italy;Jean-DanielParis,CEA,France;Jean-FrançoisRolin,IFREMER,France;KarineSelegri,CNRS,France;MichaelCunliffe,MBA/NOC,UKandThomasDirnboeck,Umweltbundesamt,Austria.

Thegoaloftheworkshopwastobuildbridgesandassesssynergiesacrossobservatorynetworks--andhowemergingenvironmentalresearchquestionsstandtobenefitfromsuchinteractions.Keyinterdisciplinarychallengeswereidentifiedacrossscientificsubdomains,aswellasstrategicopportunitiesacrossResearchInfrastructures.Specialattentionwasgiventocombiningdifferentobservatorynetworkstoadvancefrontiersciences,focusingonthepre-selectedscientificthemesidentifiedbyENVRI+communitiesmembersintheformofthefollowing4casestudies:

1. Nitrogenfromthefieldtothecoastalocean2. Phytoplanktonbloomsfromcostaltoopenocean3. Arcticobservation,withspecialfocusonCH44. SimulatingandmonitoringO3andCO2deposition/coupling/interaction

Morethan70participantswereinattendancewhentopkeynotespeakerswereaskedtoprovideacomprehensiveandin-depthanalysisofeachofthecasestudiesthatincludedwhatmaybenewdirectionsforfutureresearchandinfrastructures.Eachcasestudypresentationledtoimportantfollow-updiscussionsregardingi)whereresearchinfrastructureshaveyettobecreatedtocombinesubdomains(gapanalyses)andii)wherefurthercross-disciplinarycollaboration,interoperabilityandinfrastructureimprovementsmayberequiredforexistinginfrastructurestobesuccessful.

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1. Nitrogen,fromagriculturalfieldstothecoastalocean:theconcept

ofnitrogenbudgetsandcorollaryresearchinfrastructurescontributions

Overtherecentyears,nitrogenbudgetshavebeendevelopedinsuchawayastobecomeapracticalpolicy-makingtool.Originallyacompilationofspecificyetunconnectedindicators,nationalNbudgetsarenowcomprisedofacompletesetofNflowsthroughanation’s“metabolism”.Comprehensiveoperationaldatacollectionandcompilationhasnotbeenperformedsystematicallyyet.Growingnationalobligationstoinventoryairpollutantsandgreenhousegasemissionsalreadynowprovidethelargestshareofinformationneeded,thusfullimplementationwillrequireratherlittleextraeffort.

Intheory,Nbudgetsarefoundedontheconservationofmatter.However,morethan99%ofNstocksmaybesafelyignored,asitisunreactiveintheformofmolecularN2(themainconstituentoftheatmosphere).The“Activation”ofNisthecentral,energy-intensivestepoftheprocess,sothatonlythereactiveN(Nr)needstobeconsideredinthebudgetsofstocksandflows.SuchNrbudgetshaveprovenvaluableinprioritizingNflowsandbetterunderstandingtemporaltrendsandspatialdistributionamongecosystemtypes.

Whiletheconceptandguidancearelargelyinplace,thefewnationalbudgetscurrentlyavailablearescientificexercises.SupportfromenvironmentalagenciesandadministrationwillberequiredtocollectdataneededforabetterunderstandingoftheanthropogenicimpactontheNcycle.Thisbasicknowledgewillallowtodesignabatementactionplansaimingforalleviatingenvironmentaldamage(humanhealth,biodiversity,climatechange...)generatedbyanexcessNrintheenvironment.

InfrastructuresareinplaceintheEUtoroutinelymonitorNrcompoundsintheatmosphere(NOx,PM)aswellasingroundwater(nitrate)aspartofEUenvironmentallegislation.Talltowerstationshavebeenhavebeenlinkedtoallowinversemodellingofgreenhousegasemissions(asofN2O)inscientists’activities(TTORCH,InGOS)whichcanbeextendedbysatelliteinformationonNOxandN2OfromplatformslikeENVISAT.Biosphere-pedosphereinteractiononNrcompoundsinsoilsandgroundwaterarebeinginvestigatedinnaturalecosystems(LTER)butaremuchmorerelevantinagriculturalsystemsthatareexposedtohighlevelsoffertilizerN.ManyagriculturalresearchinstitutesoverEuropesportcollectingthisinformation,butlittlesystematicinteractioncanbeobservedacrossnationalborders.Alltheseexistingactivitiesaresectoral,butrequireanoverarchingapproach.Nitrogenbudgetsasdescribingallthelinkingelementsbetweenpoolsorsectorscanserveasthelinkurgentlyneeded.

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2. Phytoplanktonbloomsfromcoastaltoopenocean

2.1OceanicEmissions,MarineAerosolsandClouds Atmosphericaerosolsplayalargeroleinairqualityandhuman-inducedclimatechange.Afterdecadesofresearch,aerosol–cloudinteractions(ACI)remainthelargestsourceofuncertaintyincurrentestimatesofglobalradiativeforcing.Thisismainlyduetothefactthataerosols,cloudsandecosystemelementsareintricatelylinkedintheEarthSystem,viamultipleinterrelatedforcingandfeedbacks.NarrowingtheuncertaintiesinACIwouldthereforerequireconsideringallelementstogether,frombothamechanisticandobservationalstandpoint.Becauseeffectsonclimateareestimatedfromthedifferencebetweenmodelsimulations,present-dayobservationsandpreindustrialaerosolandprecursoremissions,anaccuraterepresentationofnumberconcentrationsofcloudcondensationnuclei(CCN)andicenucleatingparticles(INP)associatedwithbothnaturalbackgroundandman-madeaerosolsseparatelyiscriticalindevelopingabetterassessmentofanthropogenicaerosoleffects.Asmarineaerosolscontributesubstantiallytothepreindustrial,naturalbackgroundwhichprovidesthebaseline–ontopofwhichanthropogenicforcingshouldbequantified–andbecausetheoceancoversover70%oftheEarth’ssurface,therepresentationofmarineaerosolsinclimatemodelsstronglyinfluencesthepredicteddirectandindirectimpactsofanthropogenicaerosolsonclimate.

CurrentEarthSystemSciencemodelsexhibitalargediversityintheirrepresentationofmarineaerosolsourcesandsinks,aswellastheprocessesbywhichtheseaerosolsimpactcloudwaterandiceformation.Thisdiversityisdue,inpart,tothelackofmeasurementsneededtoconstrainthemodelsandtheabsenceofacentralizednetwork,whereallavailabledatamaybeaccessed.Measurementsofmarineaerosolsarechallengingbecauseoftheirvastspatiotemporalvariability,lowconcentrationandtotheinherentdifficultyinreproducingthephysicalscalesinwhichtheyoccur.However,eventheavailabledataishardtousebecauseofdifferencesintheconditionsiswhichtheyarecollectedandthemethodologyandinstrumentationemployedbydifferentinvestigators.Today,keyquestionsremainunansweredregardingthesourcesandsinksofmarineaerosolsandtheirimpactsonclouds,limitingourabilitytoquantitativelypredicthowtheclimatewillrespondtocontinuedandincreasinggreenhouse-gasandfine-particleemissionsinthefuture.

WeproposethatENVRI+developtheintegrativeframeworktocompileandmakeaccessibleallavailablesatellite-borne,ambientandlaboratorydataofmarineaerosolchemicalcomposition,CCNandINPs,meteorological,oceanphysicochemicalandbiologicalstate,aswellasthetracegasconcentrationsaffectingparticleproductionandtheoxidizingpotentialofthemarineatmosphere.Thisisnoteasy;thecompilationofsuchcomprehensivedatasetsinaformatsuitableformodel/datacomparisonwouldrequireacoordinatedandmultidisciplinaryresponseandtheinvolvementandexpertiseofabroadrangeofscientificcommunities.However,oncethedataiscategorizedandmadeaccessiblethroughauser-friendlynetwork,thescientificcommunitystandstosavevastamountsoftimeandenergybyavoidingunnecessaryduplications.Theexistenceofsuchdatasetswouldalsoallowresearcherstoconcentrateondataanalyses,capturingpotentiallyimportantradiativeandclimatefeedbacksanddevelopingsubsequentdiscoveries.

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2.2ObservationsforEarthSystemmodelling

Theuseofmodelstorepresentourunderstandingoftheclimatesysteminvolvescouplingradiationandwatercycleparameters(includingcloudformationandthecryosphere),withatmosphericandoceanicdynamics.Theoverarchinggoalistodevelopaclimatebaselinetobetterassesstheimpactofperturbations–anthropogenic,solar,astronomicalorvolcanic–onclimateandexplainnon-linearbehaviorsinvariousfeedbackmechanisms(which,inturn,couldenhanceorlimitsaidperturbations).

Inthepast,climatemodelswerelimitedintheirabilitytorepresentfeedbacksbecausevariousaspectsofthesystem–suchasatmosphericcompositionorvegetation–wererepresentedasfixedstaticentities.However,theEarthSystem(ES)modelsthathaveemergedoverthepastdecadeincludetherepresentationofdynamicclimatefeedbackinrelationstothecarboncycle,atmosphericaerosolsandchemistry.ThankstoESmodelling,wecannowstudyclimate-drivenchangesinoceanicCO2solubility,thebiologicalcarbonpump,landproductivitydistribution,soilrespirationandtheirultimateroleinclimatechange.

Morerecently,ESmodellinghasfocusedonvegetationandsoilsemissions(volatileorganiccompounds,methane,andnitrogenoxides)andcouplingsbetweenatmosphericcompositionandradiation-drivencomponents,suchasvegetationandcoralgrowth,evapotranspirationandriverrun-off,monsoonsystemsandpermafrostthawing.State-of-the-artESmodelstypicallyincluderepresentationsofthecarboncycle,ozonechemistry,wetlandsandpermafrost,sulfate,carbonaceous,mineraldustsandsea-saltaerosols.Themostsophisticatedmodelsalsoincludeoceanbiogeochemistry,stratosphericozonechemistryandfiremodelling,aswellasnitrateandsecondaryorganicaerosols.Researchershaveyettodevelopsatisfyingrepresentationsofthenitrogencycleandoceancalciumcarbonates,however.

Itoftentakesupto5yearstoimprovesuchmodels,seeingasextensiveobservationisrequiredtoprovideinsightsintotheprocess,developnumericalparameterizationsandultimatelytestandvalidatesubsequentresultsagainstin-situobservations.Comparativemodel-dataevaluationsmayincludestatisticsonthefrequency,strengthandtrendsofperturbations,aprioriandaposteriparameterdistributions,uncertaintybudgetcomparisons,etc...Thisensuresthatthemodelaptlyreflectstheclimatebaselineandperturbations—orinformsgapsintheory,observationsormodel(s).Spatialandtemporalscalesmismatchesareoftenachallengeinsuchcomparisons,somethingtheresearchcommunityhasnotbeenabletofullyresolve.Observationstypicallycoverhundredsofkilometersandlongtime-seriestofullysupportmodelvalidation;incontrast,processunderstandingisoftenbasedonveryfinescales.

Modelersareoftenpragmatic,ifnotopportunistic,whenseekingobservationdatasetstosupporttheirmodeldevelopmentandpredictions.Table1providesanon-exhaustivelistofdatasourcesfrequentlyusedbyatmosphericcompositionmodelers.Nevertheless,initiativesthelikesoftheObservationsforModelIntercomparisonProjectsandAerosolComparisonsbetweenObservationsandModelsprojectstrivetomakeobservationseasiertousebyprovidingmodelerswithdatasetsingriddedform,astimeseriesandinmodel-friendlyformats.BecausemanyoftherelevantprocessesoccurininterfacewithvariousEScomponents,

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ground-basedandin-situobservationsareoftenmostvaluabletomodelers,insofarastheyalsoinformonprocessesinvisibletospace-borneremotesensors.Forthatreason,astrongcaseshouldbemadetobetterpositionENVRI+networksintheglobalclimatemodellinglandscape.

Climatevariables Examplesofdatasource

Surfaceconcentrations(total,e.g.PMandspeciated)

Airqualitymonitoringnetworks(CREATE,EMEP,IMPROVE,NARSTO,STN),GAW-WDCAsites,fieldcampaigns

Aerosolopticaldepth Ground-basedsunphotometernetworks(AERONET),satelliteretrievals(MODIS,MISR,POLDER/PARASOL,VIIRS,AVHRR),reanalyses(MACC,NCEP),fieldcampaigns

Aerosolsizedistribution,fine-modefraction,Angstromexponent

EUSAAR/GUANsupersites,ground-basedsunphotometernetworks(AERONET),satelliteretrievals(MODIS,MISR,POLDER/PARASOL,VIIRS),fieldcampaigns

Totalcolumnozone Surfacespectrophotometernetwork(GMD),satelliteretrievals(SCIAMACHY,GOME,OMI)

Greenhousegases Databases(AGAGE,ESRL),satelliteretrievals(GOSAT,IASI,MOPITT,TROPOMI)

Verticalprofilesofaerosolsandozone

Lidarnetworks(EARLINET,MPLNET),satelliteretrievals(GOME,OMI),activeremotesensing(CALIPSO),aircraftcampaigns(HiPPO)

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3. Arcticobservation,withspecialfocusonCH4

TheArctichasbeenshowntohaveincreasedintemperatureby0.6oCelsiuseachdecadeforthepast30years.Thischangeisapproximatelydoubletheglobalaverageandisprojectedtoincreaseatevenfasterratesinthefuture(IPCC2013)aspartofaphenomenonreferredtoastheArcticamplification.Thiswillhaveunprecedentedeffectsonboththeoceanicandcontinentalsystemsoftheregionandmitigationhasbecomealargescientificandsocietalimperative—particularlyforArcticnativeswhorelyonsubsistenceharvests(fish,caribou,seal,walrus,waterfowl,etc.)andwhoseshorelineandhuntingandfishinghabitatarerapidlydisappearing.

IntheArcticterrestrialenvironment,permafrostdynamicsareattheheartofsuchchanges.Thetop30orsocentimetersofpermafrostnaturallythaweachyearduringthesummer.However,duetoincreasedtemperatures,thethawingofthepermafrostreachesdeepersoildepths,directlyaffectinganumberofecologicalprocesses,including

i. changesinthetemporaldynamicsanddepthofthethawoftheactivelayer,resultingin‘old’carbontorespireandeffluxmoreintotheatmosphere;

ii. subsequentchangesinsurfacehydrology;

iii. alargeportionof‘old’carbonbeingsubjecttoanaerobicmetabolismpathways,whichincreaseCH4efflux;

iv. additionalnutrientavailabilitycausingshiftsinplantcommunitycomposition,peakproductivityandwoodyencroachment;

v. increasedstorageofgroundheatfluxanddarkeralbedo,whichinturninitiateconvectiveboundarylayers,lightningandlightning-inducedtundrafires(furtherconvertingcarbonintotheatmosphere);

vi. anincreaseinthelengthofsummerandinducedseasonal‘edgeeffects’onecosystemprocesses;

vii. lakeCH4productionundericeandtheconcentrationofCH4‘bubbles’aswellas

viii. strongevidenceofCH4consumptionbysoils.

ThecontinentalscalespatialdynamicsofCH4athighlatitudesarealsopoorlyunderstood.Modelandmeasuredresultsshow‘tippingpoint’temperatures–inwhichmasspermafrostthawsandCH4productionoccurs–differintheNorthAmericancontinentandinAsia.Moreover,meanannualtemperaturesinNorthernSiberiaareincreasing,whiletheyarecoolinginSouthernSiberiabutthemechanismatplayisnotknown.

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MethanehasahigherglobalwarningpotentialthanCO2,circa28timesstrongerovera100-yearperiodandwithanaverageten-yearlifetimeintheatmosphere.TheprocessesresponsibleforthedevelopmentofCH4fromnaturalsourceshaveyettobeexplained,thoughtheyappeartobecloselylinkedtotemperatureandprecipitationandvulnerabletoclimatechange.SuchatmosphericprocessesareconsiderableandmorecomplexthanforCO2.Assuch,theprocessesanddriversthatgovernmethanogenesisandCH4reductionandconsumptionarestillthesubjectofactiveresearch.Alsohamperingground-basedmeasuresisourinabilitytodiscerntowhichextentdifferentphysicalmechanismstransportCH4fromthesoilandthebiosphereintotheatmosphere(i.e.,ebullition,diffusion,aerenchymapumping,orpressurepumping).NewaerialmeasuresofCH4derivedfromtheCARVEprojectdemonstrateemissionsarenotregionallyhomogenous,butshowhigherconcentrationsalonglargeriverbedsanddifferentgeologicsubstrates,whichthemselveswouldrequireadditionalresearchintheirownright.

ThecurrentterrestrialinfrastructureintheArcticislimited,primarilyduetoroughlogisticalandclimaticconditions.ConstrainedtoaselectnumberofcountriestheyincludetheInteract(pan-Arcticfieldstations),theITEX(pan-Arcticheatingexperiment(nowretired),theSwedishICOStower-basedproject,theNorwegianICOSstudyoffluxesfromterrestrialregions,oceanandatmosphericlevels,theNSFNEONandUSNSFAEONtower-basedprojects,theUSDOENGEEbio-geochemistrystudy,theUSNASACarveboundarylayerflightsresearch(nowretired,theUSNASAABOVEintegratedaircraftandtowersproject(intheUSandCanada)andtheEMSOEuropeanMultidisciplinarySeafloorandwater-columnObservatory.

IntheArcticoceanicandcoastalenvironments,arelativelynewsourceofCH4hasbeenreportedinmethanehydrateproduction,whichisventingthroughtheoceansandcouldpotentiallysignificantlycontributetoatmosphericconcentrations.TherearelargeamountsofCH4storedintheworld’soceansandseafloor(particularlyathigher,colderlatitudes)inasolidhydrateform(clathrates).Theyarethoughttobelocatedonoceanfloorswheresedimentscanbio-accumulateandassuch,areextremelyspatiallyheterogeneousanddifficulttodetect.Itisconsideredcoldwatertemperatures(slowreactionrates),nearcoastalareas(bio-accumulationsources)anddeepwater(pressure)areessentialtotheformationofthesedeposits.Butasoceantemperaturewarm,thereisrealconcernregardingadditionalandpossiblyrapidreleaseofsolidCH4duetoitsdestabilizationintogaseousform.AttemptstoestimatemethanehydratesfluxesareevenmoredifficultthanterrestrialCH4research,ashydratesrequireships,shiptimeandseafloorobservatories(EMSO).Becauseofsuchconstraints,measuresarecollectedthroughad-hoccruisesandevenwhenlargedepositsareformed,theirfluxesintotheatmospherearespatiallyheterogeneous.However,Methanehydratesbeingapotentialenergysource,,energyexplorationmayserendipitouslyhelpscientistsaccessandstudytheseCH4reserves.

Neverthelesslong-term,consistentmeasurements(groundandairandsea)arelacking,asareconsistentCH4measurementmethodologies(i.e.,CH4filtering,gap-fillingprocedures,spatialdistributionoftalltowerswhichcurrentlydonotexistandflasksampling,etc...).ThelogisticstoconductscienceintheArcticareclearlychallenging,withlimitedaccess,coldtemperaturesand24hofdaylightduringthesummer(andconverselyinthewinter).Theseresearchquestionsanswerstrongsocietalimperatives,andwouldwarrantthereleaseofnewandimmediateresourcesdespitethechallengesfacingresearchersworkingintheArctic.CH4releasesintotheArcticwayhaveinternationalimplicationsforoursociety,asmanycircumpolarcountrieshaveastakeinthisissue.ThroughtheArcticCouncilandinaccordancewiththeGalwaydeclaration,

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intergovernmentalcooperationtoolsshouldbeexploitedtoovercomelegalandgeopoliticalbarriersandconducttheappropriateresearch.

4. SimulatingandmonitoringO3andCO2deposition/coupling/interaction

Ozoneisahighlyreactive,toxicoxidantforplantsandisresponsibleforadecreaseinthecarbonassimilationofplantecosystems.Thissecondarypollutantisphotochemicallyformed,especiallyinareasinwhichhighUVradiationsareassociatedtohightemperaturesandthepresenceofvolatileprecursors,suchasNOxandVOCs.

Thismoleculeispresentintheatmosphereintraceconcentrations(lessthan100ppbv)andiscapableofinhibitingcarbonassimilationinagriculturalandforestecosystems.Ozoneisalotmoredifficulttomeasurethanothernon-reactivegreenhousegases.However,UV-basedandnewchemiluminescencesensorsenablepreciseandfastmeasurementsandtheiruseinexperimentalinfrastructuresishighlydesired.

Directfluxmeasurementsinthefield,usingmicrometeorologicaltechniquesinassociationwithlatentheatfluxmeasurements,allowforthepartitionofozonefluxesintodifferentsinksonthesoil-plantcontinuum:i)Stomata,ii)adsorptiononplantsurfacesandiii)gas-phasereactionswithreactiveVOCsandNOx.Experimentalevidencesuggestsstomataaloneareresponsiblefor40to80%oftheozoneremovedbyvegetation.TroposphericO3formationgeneratedbyphotochemicalreactionsinvolvingBVOCandO3mustbealsotakenintoaccountinO3budgets.

Sofar,ozoneriskassessmentshavebeenbasedonmanipulativeexperiments.Presentregulationsinassessingcriticalozonelevelsaremostlybasedonestimatedaccumulatedexposureoverathresholdconcentration.Thereishoweverascientificconsensusonfluxestimatesbeingmoreaccurate,becausetheyincludeplantphysiologyanalysesanddifferentenvironmentalparametersthatcontroltheuptake–andnotjusttheexposure--ofozone.

Long-termEddyCovariancemeasurementsofferagreatopportunitytoestimatecarbonassimilationathightemporalresolutions,soastostudytheeffectofclimatechangeonphotosyntheticmechanisms.Recentstudiessuggestwaveletandmultivariatestatisticalanalysesmaysupportourinterpretationofozonedamagetovegetation–providedozonecovariationswithenvironmentalfactors(suchaslightandtemperature)areproperlytakenintoaccount.

Whilethescientificcommunityisinvolvedinestablishinglong-termresearchinfrastructurestomeasurecarbonassimilationinresponsetoclimatechanges(e.g.ICOSnetwork),theadoptionoflow-costfastozonesensorsforEddyCovariancemeasurementswouldconstituteavaluableeffortinbetteringourunderstandingofcarbonassimilationinresponsetoenvironmentalstresses.

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CONCLUSIONS

IMPACTONPROJECTTheworkshopwasakeyelementinfindingoutsomeofthemostpressingscientificquestionswhichcouldbeansweredviainterdiciplinarycollaboration.TheworkshopresultsareparticularlyusefulfortherestoftheThemeIworkpackagesintechnicaldevelopmenprioritiesandtotheclusterstrategicprioritizationactionsinWP18.

IMPACTONSTAKEHOLDERSThedeliverableisalsoimportantfactorfortheRIprioritization,particularlyinthecontextofinternationalandcross-diciplinarycollaboration.