NOX emissions,isopreneoxidationpathways,andimplicationsforsurfaceozoneintheSoutheastUnitedStates
Katherine(Katie)TravisCMAS2016:10/26/16
Co-authors:D.J.Jacob,J.A.Fisher,P.S.Kim,E.A.Marais,L.Zhu,K.Yu,C.C.Miller,R.M.Yantosca,M.P.Sulprizio,A.M.Thompson,P.O.Wennberg,J.D.Crounse,J.M.St.Clair,R.C.Cohen,J.L.Laughner,J.E.Dibb,S.R.Hall,K.Ullmann,G.M.Wolfe,I.B.Pollack,J.Peischl,J.A.Neuman,andX.Zhou
ThisworkwassupportedbytheNASAEarthScienceDivisionandbySTAR FellowshipAssistanceAgreementno. 91761601-0 awardedby theUSEnvironmentalProtectionAgency(EPA).IthasnotbeenformallyreviewedbyEPA.Theviewsexpressedinthispresentationaresolelythoseof theauthors.
Mon
thlyM
eanSurfaceO
3
2001
Fioreetal,2009
CASTNETObservationsMulti-modelMean
TheSoutheastUSIsOneoftheMostDifficultRegionstoModelforSurfaceOzone
Blamehasincludedisoprenechemistry,isopreneemissions,drydeposition etc.
SEAC4RSFlightTracksfromDC8Aircraft
• DataUsedforthisStudyInclude:• ThomasRyerson,NOAA:NOy,NO,NO2,O3
• RonCohen,Berkeley:NO2
• PaulWennberg,Caltech:isopreneoxidationproducts
• JackDibb,UNH:HNO3
• SamHall,NCAR:J-values
SEAC4RS (Aug-Sep2013)ProvidedanUnprecedentedDatasettoInvestigateAirQualityintheSoutheastUS
GEOS-ChemIncorporatesState-of-the-ScienceUnderstandingofO3-NOx-VOCChemistry§ 0.25ox0.3125oresolutionoverNorthAmerica.§ Emissions:
§ BiogenicfromMEGAN(Guentheretal.,2012).§ SeeZhuetal,2016(ACPD)
§ SoilNOx fromHudman etal(2012).§ LightningNOx accordingtoMurrayetal.(2012).§ AnthropogenicemissionsfromEPA’sNEI2011v1.
§ Chemistry:§ ChemistryfromMaoetal.(2013).
§ Withbrominechemistry(Parrella etal.,2012).§ Improvedtreatmentoflow- andhigh- NOxpathwaystoincorporaterecentlabstudies.
§ Physicalprocesses:§ Fasterdepositionofisopreneoxidationproducts (Nguyenetal,2015).
4
1
NOx andOzoneareOverestimatedintheOriginalGEOS-ChemSimulation
SEAC4RSPIJackDibb:HNO3,ThomasRyerson:O3,NO,NO2
PBLis60%toohighforNOx and12ppbtoohighforozone.
0.0 0.2 0.4 0.6 0.8NOX, ppb
0
2
4
6
8
10
12
Altit
ude,
km
20 40 60 80 100 120O3, ppb
Mobile,108
PowerPlants,37
Industry,61
Fires,5
Soil,34
Fertilizer,13
NEI11v1(Gg N)
0.0 0.2 0.4 0.6 0.8NOX, ppb
0
2
4
6
8
10
12
Altit
ude,
km
0.0 0.5 1.0 1.5HNO3+NO3
-, ppb20 40 60 80 100 120
O3, ppb
0 20 40 60 80 100ISOPN, ppt
0
2
4
6
8
10
12
Altit
ude,
km
0 200 400 600ISOPOOH, ppt
DC8GEOS-ChemOriginal NOx
Emissions
0 50 100 150 200HPALDs, ppt
Mobile,43
PowerPlants,37Industry,24
Fires,5
Soil,31
Fertilizer,13
ReducingNEI11v1by50%ImprovesAgreementwithSEAC4RSNOyandO3
SEAC4RSPIJackDibb:HNO3ThomasRyerson:
O3,NO,NO2
0.0 0.2 0.4 0.6 0.8NOX, ppb
0
2
4
6
8
10
12
Altit
ude,
km
0.0 0.5 1.0 1.5HNO3+NO3
-, ppb20 40 60 80 100 120
O3, ppb
0 20 40 60 80 100ISOPN, ppt
0
2
4
6
8
10
12
Altit
ude,
km
0 200 400 600ISOPOOH, ppt
DC8GEOS-ChemOriginal NOx
Emissions
0 50 100 150 200HPALDs, ppt
• ManystudiesfindthatNEImobileNOx isoverestimated–• Castellanosetal,2011;Fujitaetal,2012;Yuetal,2012;Brioude etal,2013;Andersonet
al,2014.• WescaleNEI11v1by50%byreducingindustryandmobileNOx by60%.
0.0 0.2 0.4 0.6 0.8NOX, ppb
0
2
4
6
8
10
12Al
titud
e, k
m
0.0 0.5 1.0 1.5HNO3+NO3
-, ppb20 40 60 80 100 120
O3, ppb
0 20 40 60 80 100ISOPN, ppt
0
2
4
6
8
10
12
Altit
ude,
km
0 200 400 600ISOPOOH, ppt
DC8GEOS-ChemOriginal NOx
Emissions
0 50 100 150 200HPALDs, ppt
NO , ppb
Model NO Model O3x
Observed NOx Observed O3
NO and O Concentrations Below 1.5 kmx 3
O , ppb3x
SpatialVariabilityShowsNoSignificantBiases
r=0.71
Meanmodelbiasforozoneis+2ppb,9%forNOx
NOx andO3 ConcentrationsBelow1.5km
SEAC4RSPIThomasRyerson:O3,NO,NO2
O3,ppbNOx,ppb
ObservedNOx
ModelNOx ModelO3
ObservedO3
SimulationwithScaledNOx SuccessfullyCapturesIsopreneOxidationPathwaysFromSEAC4RS
DC8GEOS-ChemOriginal NOx
0.0 0.2 0.4 0.6 0.8NOX, ppb
0
2
4
6
8
10
12
Altit
ude,
km
0.0 0.5 1.0 1.5HNO3, ppb
0
2
4
6
8
10
12
20 40 60 80 100 120O3, ppb
0
2
4
6
8
10
12
0 20 40 60 80 100ISOPN, ppt
0
2
4
6
8
10
12
Altit
ude,
km
0 200 400 600ISOPOOH, ppt
0
2
4
6
8
10
12
0 50 100 150 200HPALD, ppt
0
2
4
6
8
10
12
RO2ISOPRENE +OHà HPALDISOPN
ISOPOOH
Isom. SEAC4RSPIPaulWennberg:
ISOPN,ISOPOOH,HPALD
‘HighNOxpathway’
SeeFisheretal,2016(ACP)formoreonISOPN
ReductionsinNOxHaveaSmallerImpactDueto
SpatialSegregationofEmissions
020406080100
% ISOPO2+NO
% ISOPO2+HO2
01020304050
% ISOPO2 Isomerization
01020304050
54%
26%
15%
30oN
35oN
40oN
30oN
35oN
40oN
30oN
35oN
40oN
90oW 80oW
Moredetailsin:Yu,K.etal,ACP(2016)
WeAddNewConstraintsonNOx UsingMeasurementsofDeposition
WetdepositionofNO3-
NOx =NO+NO2
NO2 +OH+Mà HNO3Verysoluble
H+ ,NO3-
DrydepositionofHNO3
MeasuredbytheNationalAtmosphericDepositionProgram
MeasuredduringSouthernOxidantandAerosolStudyJune-July2013
“WhatGoesUpMustComeDown”
WetDepositionSupportsNationalScalingofNEI11
August and September NO3
− Wet Deposition
0.0 0.1 0.2 0.3 0.4
Observed
0.0
0.1
0.2
0.3
0.4
r=0.7
NMB =8%
r=0.8
NMB =7%
Nitrate (kg N h a−1
month−1
)
0.1 0.3 0.40.20.0
(kg N h a−1
month−1
)
Modele
d (
kg N
ha−1
month
−1)
Observations (kg N ha-1 month-1)M
odel
(kg
N h
a-1m
onth
-1)
US Nitrate Wet DepositionAugust-September 2013
Reduced NOx (Bias = 7%)Original NOx (Bias = 63%)
Nitrate ((kg N ha-1
month-1)0.00.10.20.30.4
SoutheastUS:Bias=8%,r=0.71CONUS:Bias=7%,r=0.76
OzoneProductionEfficiency(OPE)ProvidesConstraintonEfficiencyofOzoneFormation
ICARTT: [Ox] = 29.0 + 14.1[NO ], r = 0.6z
OPE, Altitude < 1.5km
0 1 2 3 4 5 6 NOz, ppb
0
20
40
60
80
100
OX =
O3 +
NO
2, pp
b
GEOS-Chem:[Ox] = 27.0 + 16.7[NOz], r = 0.8SEAC4RS:[Ox] = 23.9 + 17.4[NOz], r = 0.7
OPE, Altitude < 1.5km
1 2 3 4 5
SEAC4RS:[Ox] = 23.9 + 17.4[NOz], r = 0.7
NOz, ppb
Withoutscaling,OPE=14.7whichmeansozonewouldbeproducedlessefficientlythanobserved.
SoutheastUS
HowwellcanweconstrainUSNOx emissionswithOMINO2?
>
0.001.252.503.755.001E15 molec/cm2
NO Tropospheric Column2
Observed (BEHR)
Observed (NASA)
GEOS-ChemBEHR: -18+19%NASA: -11+19%_
_
OMINO2(BEHR)
OMINO2(NASAv2.1)
GEOS-ChemwithreducedNOx emissions-18%vs.BEHR-11%vs.NASA
LowbiasinGEOS-Chem isduetouppertroposphere,notsurfaceemissions
>
0.001.252.503.755.001E15 molec/cm2
NO Tropospheric Column2
Observed (BEHR)
Observed (NASA)
GEOS-ChemBEHR: -18+19%NASA: -11+19%_
_
WithoriginalNEIemissions,Bias=+26-31%
Aug-Sep2013datawithGEOS-Chemshapefactors
Free/uppertropospheremakesmajorcontributiontoOMINO2 troposphericcolumninsummer
25-40%ofcolumn
• GEOS-ChemlowbiasinuppertroposphereiscausedbyNO/NO2 chemistry;insufficientconvectionofHOx precursorsHCHOandCH3OOH?
• CurrentOMIretrievalsmayhavelargeAMFerrors
MeanSEAC4RSNO2 profiles MeanNO/NO2 ratio
65-80%ofcolumn
[NO]/[NO2] ≈ k7/(k5[O3]) 3 2 2, ,2
O HO RO
hNO NO
n¾¾¾¾¾®¬¾¾¾¾¾
SEAC4RSPIThomasRyerson:NO2
RonCohen:NO2
DiscrepancyRemainsBetweenSurface&UpperPBLO3
CASTNET
GEOS-Chem
MDA8 ozone [ppb]25 30 36 42 48 54 60
Ozone PDF for Southeast CASTNET Sites
MDA8 ozone [ppb]
0 10 20 30 40 50 60 70 80 90 100
0.00
0.05
0.10
Observations
Model
Sites = 32
Pro
bability, ppb -1
O3
• RemaininguncertaintiesarepotentialO3 sinksandboundarylayermixing.
40ppb
48ppb
Ozone Vertical Profile Below 1.5km
50 55 60 65 70
O3, ppb
0.0
0.5
1.0
1.5
Altitude, km
Ozonesonde
GEOS-Chem
Altitud
e,km
O3,ppb
MedianOzonesonde
PI.AnneThompson
Conclusions• NEI11v1forNOx isbiasedhighacrosstheUSbyasmuchasafactorof2.• Emissionsfromindustrialandmobilesourcesmustbe30-60%lowerthanNEIvalues.• Evidenceforthiscomesfrom(1)SEAC4RSobservationsofNOx anditsoxidationproducts,(2)NADPnetworkobservationsofnitratewetdepositionfluxes.• TheOPEintheboundarylayeriswellreproduced.• TheremaybelargeerrorsinsatelliteNO2 columnsduetothepresenceofuppertroposphericNO2.Observationsshowdeparturefromphotochemicalsteady-state.• MDA8surfaceozoneisstillbiasedagainsttheCASTNETobservationsbyapproximately8ppb.
Travis,K.R.,Jacob,D.J.etal.WhydomodelsoverestimatesurfaceozoneintheSoutheastUnitedStates?, ACP,2016(inpress).
AdditionalPapersfromSEAC4RS• Organicnitrates:Fisher,J.A. etal.:Organicnitratechemistryanditsimplicationsfornitrogenbudgetsinanisoprene- andmonoterpene-richatmosphere:constraintsfromaircraft(SEAC4RS)andground-based(SOAS)observationsintheSoutheastUS,Atmos.Chem.Phys.,16,5969–5991,doi:10.5194/acp-16-5969-2016,2016.
• Formaldehyde: Zhu,L.etal.:Observingatmosphericformaldehyde(HCHO)fromspace:validationandintercomparison ofsixretrievalsfromfoursatellites(OMI,GOME2A,GOME2B,OMPS)withSEAC4RSaircraftobservationsovertheSoutheastUS,Atmos.Chem.Phys.Discuss.,doi:10.5194/acp-2016-162,inreview,2016.
• Aerosols:Kim,P.S.,Jacob,D.J.etal.:Sources,seasonality,andtrendsofsoutheastUSaerosol:anintegratedanalysisofsurface,aircraft,andsatelliteobservationswiththeGEOS-Chemchemicaltransportmodel,Atmos.Chem.Phys.,15,10411–10433,doi:10.5194/acp-15-10411-2015,2015.
• SOA:Marais,E.A. etal.:Aqueous-phasemechanismforsecondaryorganicaerosolformationfromisoprene:applicationtothesoutheastUnitedStatesandco-benefitofSO2 emissioncontrols,Atmos.Chem.Phys.,16,1603–1618,doi:10.5194/acp-16-1603- 2016,2016.
• ModelResolution:Yu,K.etal.:Sensitivitytogridresolutionintheabilityofachemicaltransportmodeltosimulateobservedoxidantchemistryunderhigh-isopreneconditions,Atmos.Chem.Phys.,16,4369–4378,doi:10.5194/acp-16-4369- 2016,2016