intercomparisonof chemical multiphase box models

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Intercomparison of Chemical Multiphase Box Models Mary C Barth 1 , Barbara Ervens 2 , Hartmut Herrmann 3 , Andreas Tilgner 3 , V Faye McNeill 4 , Ann Marie Carlton 5 , Sara Lance 6 , Mauro Morichetti 7 , Laurent Deguillaume 8 , and Nadine Chaumerliac 8 1 National Center for Atmospheric Research, Boulder, CO, United States, 2 Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States, 3 Leibniz Institute for Tropospheric Research, Leipzig, Germany, 4 Columbia University of New York, Palisades, NY, United States, 5 University of California Irvine, Irvine, CA, United States, 6 University at Albany State University of New York, ASRC, Albany, NY, United States, 7 University of Polytechnic of Marche, Ancona, Italy, 8 Laboratoire de Météorologie Physique (LaMP), Clermont-Ferrand, France Goal: Evaluate Current State of Knowledge in Multiphase Chemistry Box Models Five groups are conducting simulations in the context of the September 17-19 Whiteface Mountain Cloud Event Gas-phase chemistry has some variation among models during daytime that must be accounted for in interpretation of cloud chemistry results Cloud chemistry results show wide range of answers, especially for organic acid formation More variability found with varying pH simulation Understanding these differences is currently underway https://www2.acom.ucar.edu/cloud-chemistry Gas chemistry Aqueous chemistry Gas-liquid transfer Reference TROPOS (Tilgner, Herrmann) MCMv3.2 13,927 reactions CAPRAM4.0a 7129 reactions 275 species Tilgner et al. (2013, J. Atmos. Chem.) Deguillaume MCMv3.3.1 2043 reactions CLEPS 850 reactions 591 species Mouchel-Vallon et al. (2017, GMD) McNeill Isoprene, aromatics, and C1- C3 photochemistry 165 reactions GAMMA 239 reactions 35 species McNeill et al. (2012, ES&T) Barth Similar to MOZART4 168 reactions 45 reactions 45 species Li et al. (2017, JGR) Ervens Similar to Barth’s 168 reactions Ervens 58 reactions 22 species Ervens et al. (2014, JGR; 2008, GRL) Sample of Box Model Results Location: Whiteface Mountain: z = 1.5 km MSL, 44.4N, 73.9W Start/End times: 17:30 LT 17 Sept. / 15:00 LT 18 Sept. 30 minutes clear sky, 20 hours cloud, 30 minutes clear sky Simulation 1: Clear Sky Only Simulation 2: Cloud Water = 0.78 g/kg, pH = 4.5 Simulation 3: Cloud Water = 0.78 g/kg, pH varies as calculated by model Model Configuration Conclusions Effects of Clouds on Tropospheric Composition Acid rain studies from the 1980s and 1990s identified importance of aqueous-phase chemistry in producing sulfate Clouds affect ozone via aqueous chemistry, scattering of radiation, and lightning-NO x production Cloud chemistry can produce more secondary organic aerosols www.thelivingmoon.com Three-dimensional chemistry transport models often do not include aqueous-phase chemistry due to lack of complete understanding of the chemistry and the computational burden Goal: Evaluate the current state of knowledge in multiphase chemistry box models Background Intercomparison is being conducted in the context of the Whiteface Mountain Cloud Chemistry Study Cloud event of 17-19 September 2016 is being analyzed for its composition by several groups In this study we model the first 20 hours of the cloud event using meteorological conditions at Whiteface Mountain Clouds associated with warm front and warm sector storms/clouds Surface Weather Map 1230 UTC 17 Sept 0830 LT WFM Clouds were stratiform in nature Initial concentrations are from a WRF-Chem simulation of 16-19 September 2016 continental United States Photolysis rates from TUV v5.3 for WFM in September, for clear sky with some aerosols CCN composed of SO 4 , NH 4 , Organic Carbon Cloud drops set to 10 μm radius Meteorology of the Case Simulated Air from Ohio River Valley Variation in clear-sky results needs to be accounted for in interpreting multiphase results Gas-phase Oxidants OH has factor of 2-3 variation HO 2 has factor of ~2 variation H 2 O 2 has factor of 1-2 variation O 3 ranges from 39-44 ppbv Gas-phase HCOOH production is 50-70 pptv in three models; it does not occur in the MOZART4 gas-phase mechanism CH 3 COOH production is ~100 pptv for all mechanisms except McNeill who predict larger production of CH 3 COOH in gas phase Gas-phase Organic Acids Simulation 1: Clear Sky Only Thanks to William Gang Tsui for his contribution to McNeill’s simulations. Thanks to NCAR/ACOM for supporting cloud chemistry modeling intercomparison meeting. NCAR is supported by the National Science Foundation. Gas-phase Oxidants OH has factor of 10 variation HO 2 has factor of ~5 variation H 2 O 2 agrees well except for after cloud event O 3 ranges from 35-43 ppbv Variation in cloudy results is greater than that found in clear-sky case Gas-phase Organic Acids Aqueous-phase Organic Acids Aqueous-phase Oxidants Wide variety of answers among groups as to how much organic acids are produced, although most groups agree on CH 3 COOH production Time series of total organic acid (sum of all organic acids) will provide insight of partitioning among acids or simply different oxidation rates Simulation 2: Set LWC = 0.78 g/kg, Set pH = 4.5 cloud cloud Variation increases during daylight hours cloud cloud cloud cloud cloud cloud cloud cloud Aqueous-phase Oxidants Aqueous-phase Organic Acids Model results vary by 1-5 orders of magnitude Simulation 3: Set LWC = 0.78 g/kg, pH Varies pH values range between 4 and 4.8 cloud cloud NIGHT DAY NIGHT DAY NIGHT DAY NIGHT DAY NIGHT DAY NIGHT DAY NIGHT DAY

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Page 1: Intercomparisonof Chemical Multiphase Box Models

Intercomparison ofChemicalMultiphaseBoxModelsMaryCBarth1,BarbaraErvens2,Hartmut Herrmann3,AndreasTilgner3,VFayeMcNeill4,AnnMarieCarlton5,SaraLance6,MauroMorichetti7,LaurentDeguillaume8,andNadineChaumerliac8

1NationalCenterforAtmosphericResearch,Boulder,CO,UnitedStates,2CooperativeInstituteforResearchinEnvironmentalSciences,Boulder,CO,UnitedStates,3LeibnizInstituteforTroposphericResearch,Leipzig,Germany,4ColumbiaUniversityofNewYork,Palisades,NY,UnitedStates,5UniversityofCaliforniaIrvine,Irvine,CA,UnitedStates,6UniversityatAlbanyStateUniversityofNewYork,ASRC,Albany,NY,UnitedStates,7UniversityofPolytechnicofMarche,Ancona,Italy,8LaboratoiredeMétéorologie Physique(LaMP),Clermont-Ferrand,France

Goal:EvaluateCurrentStateofKnowledgeinMultiphaseChemistryBoxModels

• FivegroupsareconductingsimulationsinthecontextoftheSeptember17-19WhitefaceMountainCloudEvent

• Gas-phasechemistryhassomevariationamongmodelsduringdaytimethatmustbeaccountedforininterpretationofcloudchemistryresults

• Cloudchemistryresultsshowwiderangeofanswers,especiallyfororganicacidformation

• MorevariabilityfoundwithvaryingpHsimulation• Understandingthesedifferencesiscurrentlyunderway

https://www2.acom.ucar.edu/cloud-chemistry

Gaschemistry Aqueouschemistry Gas-liquidtransfer Reference

TROPOS(Tilgner,Herrmann)

MCMv3.213,927reactions

CAPRAM4.0a7129reactions 275species Tilgner etal.(2013,J.

Atmos.Chem.)

Deguillaume MCMv3.3.12043reactions

CLEPS850reactions 591species Mouchel-Vallon etal.

(2017,GMD)

McNeill

Isoprene,aromatics,andC1-C3 photochemistry

165reactions

GAMMA239reactions 35species McNeilletal.(2012,

ES&T)

BarthSimilartoMOZART4

168reactions45reactions 45species Lietal. (2017,JGR)

Ervens SimilartoBarth’s168reactions

Ervens58reactions 22species Ervens etal.(2014,

JGR;2008,GRL)

SampleofBoxModelResults

• Location:WhitefaceMountain:z=1.5kmMSL,44.4N,73.9W

• Start/Endtimes:17:30LT17Sept./15:00LT18Sept.

• 30minutesclearsky,20hourscloud,30minutesclearsky

• Simulation1:ClearSkyOnly

• Simulation2:CloudWater=0.78g/kg,pH=4.5

• Simulation3:CloudWater=0.78g/kg,pHvariesascalculatedbymodel

ModelConfiguration ConclusionsEffectsofCloudsonTroposphericComposition

• Acidrainstudiesfromthe1980sand1990sidentifiedimportanceofaqueous-phasechemistryinproducingsulfate

• Cloudsaffectozoneviaaqueouschemistry,scatteringofradiation,andlightning-NOx production

• Cloudchemistrycanproducemoresecondaryorganicaerosols

www.thelivingmoon.com

• Three-dimensionalchemistrytransportmodelsoftendonotincludeaqueous-phasechemistryduetolackofcompleteunderstandingofthechemistryandthecomputationalburden

• Goal:Evaluatethecurrentstateofknowledgeinmultiphasechemistryboxmodels

Background

• Intercomparison isbeingconductedinthecontextoftheWhitefaceMountainCloudChemistryStudy

• Cloudeventof17-19September2016isbeinganalyzedforitscompositionbyseveralgroups

• Inthisstudywemodelthefirst20hoursofthecloudeventusingmeteorologicalconditionsatWhitefaceMountain

Cloudsassociatedwithwarmfrontandwarmsectorstorms/clouds

SurfaceWeatherMap1230UTC17Sept0830LT

WFM

Cloudswerestratiform innature

• InitialconcentrationsarefromaWRF-Chem simulationof16-19September2016continentalUnitedStates

• PhotolysisratesfromTUVv5.3forWFMinSeptember,forclearskywithsomeaerosols

• CCNcomposedofSO4,NH4,OrganicCarbon

• Clouddropssetto10µmradius

MeteorologyoftheCaseSimulated

AirfromOhioRiverValley

Variationinclear-skyresultsneedstobeaccountedforininterpretingmultiphaseresults

Gas-phaseOxidants

OHhasfactorof2-3variation HO2 hasfactorof~2variation

H2O2 hasfactorof1-2variation

O3 rangesfrom39-44ppbv

• Gas-phaseHCOOHproductionis50-70pptvinthreemodels;itdoesnotoccurintheMOZART4gas-phasemechanism

• CH3COOHproductionis~100pptv forallmechanismsexceptMcNeillwhopredictlargerproductionofCH3COOHingasphase

Gas-phaseOrganicAcids

Simulation1:ClearSkyOnly

ThankstoWilliamGangTsui forhiscontributiontoMcNeill’ssimulations.ThankstoNCAR/ACOMforsupportingcloudchemistrymodelingintercomparison meeting.NCARissupportedbytheNationalScienceFoundation.

Gas-phaseOxidants

OHhasfactorof10variationHO2 hasfactorof~5variation

H2O2 agreeswellexceptforaftercloudevent

O3 rangesfrom35-43ppbv

Variationincloudyresultsisgreaterthanthatfoundinclear-skycase

Gas-phaseOrganicAcids Aqueous-phaseOrganicAcids

Aqueous-phaseOxidants

• Widevarietyofanswersamonggroupsastohowmuchorganicacidsareproduced,althoughmostgroupsagreeonCH3COOHproduction

• Timeseriesoftotalorganicacid(sumofallorganicacids)willprovideinsightofpartitioningamongacidsorsimplydifferentoxidationrates

Simulation2:SetLWC=0.78g/kg,SetpH=4.5

cloud cloud

Variationincreasesduringdaylighthours

cloudcloud

cloud cloud

cloudcloud

cloudcloud

Aqueous-phaseOxidants

Aqueous-phaseOrganicAcids

Modelresultsvaryby1-5ordersofmagnitude

Simulation3:SetLWC=0.78g/kg,pHVaries

pHvaluesrangebetween4and4.8

cloudcloud

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