1. Harvard University and NASA/GFSC
Evaluation of GMI simulations with TES ozone data: indirect validation of TES
Jennifer Logan, Bryan Duncan, Jose Rodriguez, Lin Zhang, Inna Megretskaia, and the TES and GMI Science Teams
Harvard University and NASA/GFSC
AGU, December 15, 2006

2. The Global Modeling Initiative (GMI) ‘Combo’ Model
‘Combo’ = tropospheric + stratospheric chemical mechanism (122 species, >300 thermolytic rxns, 78 photolytic rxns)
Stratospheric heritage from Goddard model
Tropospheric heritage in part from GEOS-Chem
Meteorological fields from GEOS-4: DAS, DAS Forecast and GCM
2° latitude x 2.5° longitude resolution
~1 km resolution below 10 hPa (lid at hPa)
3 hr updates using 3-hr averages

3. This model output is available to the community for Aura science.
GMI and Aura
The Combo model has been run using assimilated meteorological fields for the Aura period (so far, Feb Dec. 2005).
This model output is available to the community for Aura science.
We have been evaluating the Combo simulation for the troposphere and comparing to TES ozone data.
Daily ozone fields were archived.
Note – these are preliminary results, model updates are in progress.
In the next, improved version, daily ozone, CO and other fields will be archived, as required by the Aura teams.

4. Strategy
By evaluating the model with in-situ data, we learn where the model does well and where there are deficiencies.
Profile data available for ~50 locations (sondes and MOZAIC).
Having “calibrated” the model performance, compare the model and TES ozone.
If the model and TES agree where we know the model does well, we are confident that the discrepancies in other regions are “real”.
Explore the causes of these discrepancies

5. Ozone at N. extratropics, DAS and FVGCM
The DAS run looks great for tropospheric ozone
(see gmi.gsfs.nasa.gov for strat. evaluation by S. Strahan).

6. Sub-tropics and tropics, DAS and FVGCM
DAS very low in BB season (NH and SH) in S. Atlantic

7. Ozone at 500hPa (MOZAIC data)
FVGCM
DAS
Ozone at 500hPa (MOZAIC data)
South
U.S.
E. Atlantic
Middle
East
S. Asia

8. DAS vs. in-situ data 500 hPa
JULY
OCTOBER

9. TES – DAS comparisons
Focus on July to December, 2005.
TES data much sparser before July 2005, before routine limb soundings were dropped.
TES validation with sondes shows TES is biased high by ~5 ppb at 500 hPa (Nassar et al., Richards et al).
Model sampled at TES profile locations on same day, and AKs and prior applied.
TES prior from MOZART model
Results gridded on 2x2.5 grid
Difference [(DAS with AK) –TES] removes prior

10. Combo-DAS vs. TES ozone, 511 hPa, July 2005
DAS with AK
DAS (w. AK/prior) –TES
(removes
prior)

11. Are TES comparisons consistent with validation of Combo-DAS using in-situ data?
TES comparison in July implies DAS is:
Too low in N. tropical Atlantic
Too high over U.S.
Too low over W. Europe
OK in Middle East
OK in S. Atlantic
TES results consistent with in-situ data where available
Indirect validation of TES possible
Shows model deficiencies

12. Combo-DAS vs. TES ozone, 511 hPa, October, 2005

13. In situ data confirms the underestimate over the S
In situ data confirms the underestimate over the S. tropical Atlantic, and in the large scale ozone plume
TES comparisons show the extent of the underestimate

14. Combo-DAS vs. TES, December, 2005

15. DAS –TES Differences, July – December
Regions where model is too high, as well as too low
JULY
OCT.
AUG.
NOV
SEPT.
DEC

16. They show regions of overestimate of ozone in:
Summary
The COMBO-DAS looks remarkably like sonde/MOZAIC data in many regions
Major discrepancies from sonde/MOZAIC data are in the tropical Atlantic sector, in the biomass burning season
TES comparisons show the spatial extent of the underestimate of ozone in:
the N. tropical Atlantic in July, less so in August
N and S. tropical Atlantic in August
Brazil, equatorial Atlantic and Africa in October, November
Central Africa in December
They show regions of overestimate of ozone in:
Eastern Indian Ocean in October - December
Next step: Improved emissions of NOx in model, use Forecast fields (Duncan et al. ).