1. Validation of TES Methane with HIPPO Observations For Use in Adjoint Inverse Modeling Kevin J. Wecht 17 June 2010TES Science Team Meeting Special thanks to: Annmarie Eldering Daniel JacobSteve Wofsy Susan KulawikLin ZhangEric Kort Greg OstermanChristopher Pickett-Heaps Vivienne Payne

2. Adjoint Inverse Modeling of Methane Sources Adjoint inverse analysis OPTIMIZATION OF SOURCES GEOS-Chem CTM Validation HIPPO 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)

3. HIPPO HIPPO 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 path Vertical Profile Flight path Vertical Profile Photos courtesy: S. Wofsy

4. HIPPO vs. TES by Latitude RTVMR [ppb] HIPPO I Jan 9-30, 2009 HIPPO II Oct 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

5. HIPPO vs. TES by Latitude RTVMR [ppb] HIPPO I Jan 9-30, 2009 HIPPO II Oct 22 – Nov 20, 2009 HIPPO I:bias = 73.6 ppb,residual error = 41.1 ppbn = 129 HIPPO II:bias = 61.0 ppb,residual error = 44.8 ppbn = 147 TES over land TES over ocean Mean Bias

6. Distribution of Residual Error HIPPO I Errors are normally distributed, important for derivation of inversion cost function. HIPPO II also shows Gaussian residual error. Histograms of HIPPO – TES difference All Observations Land ObservationsOcean Observations mean = 73.6 σ = 41.1 n = 129 mean = 78.0 σ = 37.3 n = 90 mean = 63.7 σ = 47.8 n = 39 Mean and standard deviation in units [ppb]

7. Collocation Error Mean Bias Quantify observation, representation error. Error and bias differ for HIPPO I and II. TES self-reported instrument error is ???- ??? % ≈ ???-??? ppb HIPPO I HIPPO II Residual Error TES bias and residual error vs. size of coincidence window Observation error [ppb] Distance [km] 125 250 375 500 Distance [km] 40 120 80 0 40 120 80 0 # Observations 24 hour 12 hour

8. Model Comparison TES and GEOS-Chem along HIPPO I flight track TES and GEOS-Chem averaged over the Pacific during the HIPPO I period HIPPO I Jan 9-30, 2009 RTVMR [ppb] Consistency with HIPPO GEOS-Chem w/ TES op. TES HIPPO w/ TES op.

9. Model Comparison RTVMR [ppb] Consistency with HIPPO HIPPO II Oct 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.

10. Model Comparison – NOAA GMD 2008 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 GEOS-Chem [ppb] NOAA GMD [ppb] [ppb] Latitude GEOS-Chem is a good platform inter-comparison of data sets such as TES methane. [ppb] GEOS-Chem NOAA GMD

11. Model Comparison – TES 2009 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. Difference [ppb] RTVMR [ppb] GEOS-Chem w/ TES operator RTVMR GEOS-Chem GEOS-Chem w/ TES op. TES

12. Model Comparison TES 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-Chem GEOS-Chem w/ TES op. TES

13. Adjoint Inverse Modeling of Methane Sources Adjoint inverse analysis OPTIMIZATION OF SOURCES GEOS-Chem CTM Validation HIPPO 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 additional satellite products

14. Thank You! TES captures latitudinal gradient in HIPPO data TES is biased high but residual instrument error is within self-reportedrange – 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.