Validation of TES Methane with HIPPO Observations

For Use in Adjoint Inverse Modeling

Kevin J. Wecht17 June 2010TES Science Team Meeting

Special thanks to:Annmarie Eldering Daniel Jacob

Steve WofsySusan Kulawik Lin Zhang

Eric KortGreg Osterman Christopher Pickett-HeapsVivienne Payne

Adjoint Inverse Modeling of Methane Sources

Adjoint inverse analysis

OPTIMIZATION OF SOURCES

GEOS-Chem CTM

ValidationHIPPO

Methane(Wofsy, Kort)

Apriori Sources

GEOS-Chem Adjoint

EDGAR v4, Kaplan, GFED 2, Yevich and Logan [2003]

HIPPO Methane provides:• Large number of profiles• Wide latitudinal coverage• Remote from sources

(reduces collocation error)

TES Methane (Worden, Kulawik)

HIPPOHIPPO I HIPPO II

January 9-30, 2009 October 22 - November 20, 2009

138 vertical profiles 147 vertical profiles

HIAPER Pole-to-Pole Observation Program

• Five missions:- Jan, Nov 2009- April 2010, June & Aug 2011

• > 700 vertical profiles by finish- 80% surface – 330 hPa- 20% surface – < 200 hPa

• Methane Instrument Properties- Frequency: 1 Hz- Accuracy/Precision: 1.0/0.6 ppb

Flight pathVertical Profile

Flight pathVertical Profile

Photos courtesy: S. Wofsy

HIPPO vs. TES by Latitude

RTVM

R [

ppb]

RTVM

R [

ppb]HIPPO I

Jan 9-30,2009

HIPPO IIOct 22 – Nov 20,

2009

TES observation operator is applied to all profiles unless explicitly stated.Positive bias and significant noise, but latitudinal gradient is captured.

TES

HIPPO w/ TES op.HIPPO 250-450 hPa

HIPPO vs. TES by Latitude

RTVM

R [

ppb]

RTVM

R [

ppb]HIPPO I

Jan 9-30,2009

HIPPO IIOct 22 – Nov 20,

2009

HIPPO I: bias = 73.6 ppb, residual error = 41.1 ppb n = 129HIPPO II: bias = 61.0 ppb, residual error = 44.8 ppb n = 147

TES over landTES over ocean

Mean Bias

Distribution of Residual ErrorHIPPO I

Errors are normally distributed, important for derivation of inversion cost function.

HIPPO II also shows Gaussian residual error.

Histograms ofHIPPO – TES difference

All Observations

Land ObservationsOcean Observations

mean = 73.6σ = 41.1n = 129

mean = 78.0σ = 37.3n = 90

mean = 63.7σ = 47.8n = 39

Mean and standard deviation in units [ppb]

Collocation Error

Mean Bias

Quantify observation, representation error. Error and bias differ for HIPPO I and II.

HIPP

O I

HIPP

O II

Residual ErrorTES bias and residual error vs. size of coincidence window

Observation error

[ppb

][p

pb]

Distance [km]125 250 375 500

Distance [km] Distance [km]

40

120

80

0

40

120

80

0

# Observations24 hour12 hour

Model ComparisonTES and GEOS-Chem along HIPPO I flight track

TES and GEOS-Chem averaged over the Pacific during the HIPPO I period

HIPPO IJan 9-30,

2009

RTVM

R [

ppb]

RTVM

R [

ppb]

Consistency with HIPPO

GEOS-Chem w/ TES op.TES

HIPPO w/ TES op.

Model Comparison

RTVM

R [

ppb]

RTVM

R [

ppb]

Consistency with HIPPO

HIPPO IIOct 22 – Nov 20,

2009

TES and GEOS-Chem along HIPPO II flight track

TES and GEOS-Chem averaged over the Pacific during the HIPPO II period

GEOS-Chem w/ TES op.TES

HIPPO w/ TES op.

Model Comparison – NOAA GMD2008 Annual Average

• GEOS-Chem provides good simulation in the annual average• Seasonality to inter-hem. gradient• Missing northern hemisphere sources? Natural gas production?

[ppb]

GEOS-Chem and GMD surface methane

GE

OS

-Che

m [p

pb]

NOAA GMD [ppb]

[ppb

]Latitude

GEOS-Chem is a good platform inter-comparison of data sets such as TES methane.

[ppb

]

GEOS-ChemNOAA GMD

Model Comparison – TES2009 Annual Average

• TES captures variability in GEOS-Chem, with large residual error.• Interpretation of latitudinal profile complicated by latitudinal structure of DOFS • Model overestimate around equator.

Diff

eren

ce

[ppb

]R

TVM

R [

ppb]

GE

OS

-Che

m w

/ TE

S o

pera

tor

RTV

MR

GEOS-ChemGEOS-Chem w/ TES op.TES

Model ComparisonTES RTVMR w/

mean TES – GEOS-Chem difference subtracted

GEOS-Chem RTVMR

[ppb]

Difference: GEOS-Chem – TES

[ppb]

TES a priori RTVMR

Quantitative source attribution of differences requires inverse modeling.

GEOS-ChemGEOS-Chem w/ TES op.TES

Adjoint Inverse Modeling of Methane Sources

Adjoint inverse analysis

OPTIMIZATION OF SOURCES

GEOS-Chem CTM

ValidationHIPPO

Methane(Wofsy, Kort)

Apriori Sources

GEOS-Chem Adjoint

EDGAR v4, Kaplan, GFED 2, Yevich and Logan [2003]

TES Methane (Kulawik, Osterman)

4D-Var assimilation of TES data:• Optimize emissions on

– 2x2.5 horizontal grid– monthly temporal res.

• Evaluate results with HIPPO, NOAA GMD

• Incorporation of additionalsatellite products

Thank You!

• TES captures latitudinal gradient in HIPPO data• TES is biased high but residual instrument error is within self-reported range

– 73.6 ± 41.1 ppb during HIPPO I– 61.0 ± 44.8 ppb during HIPPO II

• Pending prognosis of TES instrument, will validate again with HIPPO IV & V• Enabling Inverse Modeling:

– Time period: TES provides useful information through the end of HIPPO II.– Quantification of bias, observation error, and representation error.– Error normally distributed.– Robust latitudinal gradient with greater coverage than surface stations

• HIPPO and NOAA GMD will be used to evaluate inversion results.• Future incorporation of additional satellite products.