Valida&onofTESMethanewithHIPPOObserva&ons

Applica&ontoAdjointInverseModelingofMethaneSources

KevinJ.Wecht,DJJacob,SCWofsy,EAKort,AEldering,JRWorden,SSKulawik,GBOsterman,VHPayne

29September2010AuraScienceTeamMee&ng

AdjointInverseModelingofMethaneSources

Adjointinverseanalysis

OPTIMIZATIONOFSOURCES

GEOS‐ChemCTM

Valida&onHIPPO

Methane(Wofsy,Kort)

AprioriSources

GEOS‐ChemAdjoint

EDGARv4,Kaplan,GFED2,YevichandLogan[2003]

HIPPOMethaneprovides:• Largenumberofprofiles• Widela&tudinalcoverage• Remotefromsources(reducescoloca&onerror)

TESMethane(Worden,Kulawik)

OtherMethane

TESV004CH4

• Methaneretrieval7.658–7.740μm• Averagingkernelspeak200‐400hPa• DegreesofFreedomforSignal0.5‐2.0• ~50%ofTESobserva&onspassCH4qualityfilter• Unitofcomparisonforthisworkis

Representa&veTroposphericVolumeMixingRa&o(RTVMR)

RowsofTypicalAveragingKernel

RTVMR(Payneet.al.2009)• Mapretrievalto4‐levelpressuregriddefinedbyAK.• Concentra&onat2ndpressurelevelistheRTVMR.

0 0.05 0.10 1600 1700 1800 1900[ppb]0.00 0.05 0.10 0.15

1000

100

10

Pre

ssure

[hP

a]

100mb500mb1000mb( Sum of Rows of AK ) / 10

1500 1600 1700 1800 1900 2000[ppb]

1000

100

10P

ressure

[hP

a]

TESTES apriori

Pressure[h

Pa]

10

1000

100

aprioriTES

CorrespondingCH4Retrieval RTVMRGrid

Reduceallprofilesto1pieceofinforma4onrepresenta4veoftroposphericmixingra4o.

HIAPERPole‐to‐PoleObserva&onProgram(HIPPO)

HIPPOI‐interpolatedmethanePacifictransect(flights3‐7of10)Dominantvariabilitywithla&tudeLiklevariabilityinver&cal

• Fivemissions:- Jan,Nov2009- April2010,June&Aug2011

• >700ver&calprofilesbyfinish- 80%surface–330hPa- 20%surface–<200hPa

• MethaneInstrumentProper&es- Frequency:1Hz- Accuracy/Precision:1.0/0.6ppb

Pressure[h

Pa]

1000

800

600

400

200

La&tude0 20 6040‐60 ‐20‐40 80

1600 1775 1950[ppb]

HIPPOI HIPPOII

UsingHIPPOtoDefineCoincidenceCriteria

Mean Bias

HIPPO

I

Residual Standard Dev.

[ppb

]

# Observations

Coincidencerequirementsof+/‐750kmand+/‐24haresufficient.

Standarderrorofthemean

250 375 500 625 750Distance [km]

30

40

50

60

70

80

90

100

250 375 500 625 750Distance [km]

10

20

30

40

50

60

70

80R

esid

ua

l E

rro

r [p

pb

]

250 375 500 625 750Distance [km]

0

40

80

120

160

24hour

12hour24hour

12hour

~250km

HIPPOprofiles

TESobserva&on 5x8km

Valida&oncharacterizesmeanbiasandresidualerror.Residualerrorcontainscontribu&onsfrom:1)errorintheretrieval2)coloca&onerror r

‐6h+20h

250 500 750 250 500 750 250375

750500625

Distance[km]Distance[km]

N

HIPPOv.TESbyLa&tude

-60 -40 -20 0 20 40 60 80

Latitude

1700

1800

1900

2000

-60 -40 -20 0 20 40 60 80

Latitude

1700

1800

1900

2000

RTVM

R[pp

b]

RTVM

R[pp

b]

HIPPO1Jan9‐30,2009

HIPPO2Oct22–Nov20,

2009

Posi4vebiasandsignificantnoise,butla4tudinalgradientroughlycaptured.

TES

HIPPOw/TESop.

HIPPO250‐450hPa

#TES=204#HIPPO=76

#TES=183#HIPPO=72

HIPPOv.TESDifferencebyLa&tude

HIPPO1Jan9‐30,2009

HIPPO2Oct22–Nov20,

2009

-60 -40 -20 0 20 40 60 80

Latitude

-100

0

100

200

300

-60 -40 -20 0 20 40 60 80

Latitude

-100

0

100

200

300

RTVM

R[pp

b]

RTVM

R[pp

b]

TES–HIPPOoverlandTES–HIPPOoverocean

MeanBias

HIPPOI: bias=73.7ppb, residualstddev=43.1ppb ≈3xself‐reportederrorHIPPOII: bias=59.9ppb, residualstddev=48.4ppb marginallysig.land‐oceandiff

Distribu&onofTESResidualErrors

HIPPOI1/9‐1/30,

2009

HIPPOII10/22–11/20,

2009

Normallydistributederrorsareimportantforderiva4onofinversecostfunc4on.

ScakerplotsErrordistribu&ons

-100 -50 0 50 100 150 200 250Difference [ppb]

0

5

10

15

20

25

30#

Occu

ran

ce

s

-100 -50 0 50 100 150 200 250Difference [ppb]

0

5

10

15

20

25

30

# O

ccu

ran

ce

s

1650 1700 1750 1800 1850 1900 1950 2000

HIPPO RTVMR

1700

1800

1900

2000

TE

S R

TV

MR

1650 1700 1750 1800 1850 1900 1950 2000

HIPPO RTVMR

1700

1800

1900

2000

TE

S R

TV

MR

TESRT

VMR[ppb

] 2000

1900

1800

1700

2000

1900

1800

1700TESRT

VMR[ppb

]

HIPPORTVMR[ppb]1700 1800 1900

N=76r=0.65

N=72r=0.59

bias=73.3σ=43.1

bias=59.9σ=48.4

-60 -40 -20 0 20 40 60 80Latitude

1650

1700

1750

1800

1850

1900

1950

RT

VM

R [ppb]

TheAbilityofTEStoCaptureLa&tudinalGradients

TEScapturesHIPPOI&IIla4tudinalgradientsonascaleof~20°

HIPPOI15°La&tudeBins

HIPPOIandTESGradientsTESHIPPO

Latitude 0 20 6040‐60 ‐20‐40-60 -40 -20 0 20 40 60 80Latitude

-2

-1

0

1

2

3

4

Gra

die

nt [p

pb/d

eg]

Gra

dien

t [pp

b / °

lat]

0

2

‐2

4

RTVM

R [p

pb] 1900

1800

1700

Bin Size [° latitude] 0 20 6040 80

[ppb

/ °la

t]

0

1

2

3

4

5

0 20 40 60 80 100Bin Size [Degrees Latitude]

0

1

2

3

4

5

Std

de

v o

f T

ES

-HIP

PO

gra

die

nts

mean(|HIPPO|)mean(|TES–HIPPOdifference|)

TwinTestsforInversionofMethaneSources

Whyperformtwintests?• Testtheinversecalcula&on• UnderstandtheeffectsofTESerrorandapriori• Findop&mumlengthofassimila&onperiod

Thetwintestmethodology• “Observe”GEOS‐ChemwithTES• Adderrortopseudo‐observa&onsofmagnitudedeterminedbyHIPPOvalida&on• Beginadjointinversionwithincorrectapriori• Goal:torecoveroriginalemissionfield.

GEOS‐ChemRTVMRJuly2008

w/error

Aprioriemissions

=‐50% =+50%

#ofObserva&onsJuly2008total=22038 ppb

TwinTestResults

Assimila4onLength #observa4ons

Top 1month 22038

Middle 2months 40060

Bokom 1year 199588

Tradeoffbetweennumberofobserva4onsandspa4alresolu4onofemissionsTESV004aloneisnotsufficientforuseinaglobaladjointinversion

0 +50%‐50%2.0 4.0 6.00

102MgCH4

July2008CH4Emissions

Op&mizeJuly2008emissions,assimila&ngdataforvariablelengthsof&me.

1month

2months

1year

op&mized‐truetrue

NextSteps

•  AssimilateTESV004CH4

•  EvaluateinversionresultswithNOAAGMDsurfaceobserva&ons

•  ValidatenewTESCH4retrievalbyJohnWorden–  sensi&vitynearsurface

•  Assimilatemoresatelliteproducts(NewTESCH4,SCIAMACHY,AIRS,GOSAT).

•  ZoominonNorthAmericausingGEOS‐Chemnestedgridcapability(0.5°x0.667°)

NewTESCH4retrievalRowsofAveragingKernel

Pressure[h

Pa]

100

10000 0.2 0.4 0 0.2 0.4

Courtesy:JohnWorden

Iwillsimultaneouslyassimilatemul4plesatellitedatasets

•  TEScapturesla&tudinalgradientinHIPPOdataat~20°resolu&on

•  TESisbiasedhighandresidualinstrumenterroris3xself‐reportedrange–  73.7±43.1ppbduringHIPPOI–  59.9±48.4ppbduringHIPPOII

•  Coloca&onerrorinvalida&onisnegligible•  IntendtopublishresultsofHIPPOcomparison.

•  EnablingInverseModeling:–  Quan&fica&onofbias,characteriza&onoferror–  Robustla&tudinalgradientwithgreatercoveragethansurfacesta&ons–  Assimila&onperiod≥1monthrequired.

–  Tradeoffbetweenlengthofassimila&onperiodandspa&alscaleofinterpretabilityofresults

•  BegininversionwithTESCH4

•  EvaluateinversionresultswithNOAAGMDsurfaceobserva&ons

•  Incorporateaddi&onalsatelliteCH4productsandfocusonN.A.

ThankYou!