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!