nox emissions, isoprene oxidation pathways, and...

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.

ktravis@fas.harvard.edu

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