TES Validation: Results from the First Twelve Months and Planning for Future Opportunities

1. TES Validation: Results from the First Twelve Months and Planning for Future Opportunities TES Science Team Jet Propulsion Laboratory/ California Institute of Technology AVE/PAVE Science Team Meeting September 20, 2005

2. Overall Validation Status of TES L2 Data (v001) • The TES L2 nadir products have undergone an initial set of quality control and validation. • The current TES L2 data products (v001) available to the public are considered a “beta” release as of July 2005. • Version 001 TES data was made publicly available in July 2005. • The effort to validate the TES L2 products is in the process of being expanded and will provide more comprehensive comparisons in the near future.

3. Data Quality of TES Data Products (v001) • Level 1B: • TES L1B data products have systematic errors that will be fixed in v002 data. • Systematic errors are estimated after radiometric calibration and show an average radiance error of approximately 2% . • Errors specific to each target spectrum are available within the data products. • Level 2: • TES L2 products that are ready for scientific use are nadir retrievals of ozone, carbon monoxide, temperature and water for ocean target scenes. • Caveats on TES L2 Products: • Land scenes are reported but are not reliable due to a known software bug. • TES L2 retrievals over desert have problems with the a priori estimates of emissivity and should not be used. • Retrieved parameters poleward of 60 should be used with caution due to the low brightness temperatures associated with these scenes. • As a means of accounting for systematic errors in L1B radiances, current L2 profiles include the retrieval of a calibration scaling parameter. • The error estimates included in the L2 data products are meaningful based on the current validation analysis.

4. TES Measurement Status • Global Surveys (with limb scans) taken Sep 2004 – Apr 2005 • 73 16-orbit Global Surveys acquired with limb data • Nadir targets ~5°apart along orbit track (2 nadir scans averaged) • Global Surveys without limb scans started May 2005 • 3x more nadir targets, ~1.6° separation, no averaging of scenes • Limb mode still available for special observations, but removed from the Global Survey mode to preserve instrument lifetime. • No data for June 2005 due to instrument in safe mode. • Current pause in data collection due to sudden rise in ICS (interferometer control system) motor current. • Step/Stare, Stare and Transect modes used for special observations • AVE Oct 2004 – Nov 2004 & PAVE Jan 2005 – Feb 2005 • S. Atlantic Sep 2004 – Oct 2004, Jan 2005 – Feb 2005 • N. America July 31, 2005 – August 6, 2005 • Lake Tahoe (Stare mode for geolocation, radiance val.) Aug 05 – Sep 05 • S. America (biomass burning transects) Aug 2005 – Sep 2005

5. TES Data Availability • Current TES data at the Langley ASDC is v1.0, Beta • Nadir scenes only. • L2 retrievals from special observations to start delivery Oct 2005. • Caveats listed for L1B calibration and L2 land retrieval issues. • Data taken during AVE 04 available at AVDC. • Data taken during PAVE 05 to be delivered to AVDC Sep 2005. • Next release (v2.0) in spring 2006 • L1B calibration improved substantially & validated • Will include limb retrievals (with HNO3) • HDO product added for nadir views

6. L2 Product Available at DAAC: Blue = Global Survey data available, Dark Grey = data to be delivered, Light Grey = Focal Plane De-ice

7. Radiance Validation (Launch + 14 Months) • Key Results: • Comparisons between TES L1B radiance spectra and those from AIRS show that they agree to less than 1K in brightness temperature (improved for v002 data). • Comparisons with AIRS and Scanning-HIS show biases due to systematic errors that are being investigated.

8. Ozone Validation (Launch + 14 Months) • Key Result: Comparisons with sondes show a consistent bias toward larger ozone concentrations in the upper troposphere measured by TES.

9. TES Ozone Validation • Able to detect expected variability in the lower troposphere • Bias in the upper troposphere (peaked at 200 - 150 hPa)

10. Carbon Monoxide Validation (Launch + 14 Months) • Key Results: • Comparisons between TES and MOPITT at pressure layers where both instruments are most sensitive show that the retrievals agree to within roughly 10% • Comparisons between TES and Argus agree to within the TES measurement error. • GEOS-Chem and TES data show the same broad latitudinal structure in CO at all altitudes and consistent inter-hemispheric gradients.

11. Water Vapor Validation (Launch + 14 Months) • Key Results: • TES total column water vapor is 10% drier than AMSR-E and AIRS. • Most of the difference in the column is seen in the 700-900mb layer. • Initial comparisons of TES water retrievals to aircraft instruments show good qualitative agreement.

12. Temperature Validation (Launch + 14 Months) • Key Results: • Comparisons of AIRS and TES temperature data show that the temperature profiles agree to within 2K. • The vertical structure of the difference between TES and AIRS profiles is consistent from day to day. • Preliminary results show excellent agreement to Reynolds Optimally Interpolated SST with overall bias of ~0.1K.

13. HDO Validation (Launch + 14 Months) • Key Results: • TES sensitive to HDO in the mid-upper troposphere. • Initial comparisons with ALIAS look very encouraging.

14. Primary TES L2 Issues (Next 12 Months) • Ozone in the Upper Troposphere • Understand and mitigate the bias currently seen in TES profiles and total column • Carbon Monoxide • More profile comparisons with data under a wider range of CO mixing ratios to better understand TES retrievals • Water Vapor and Temperature • Better understanding of water vapor retrievals in the middle troposphere • Reasons for 2 K bias seen in comparisons with AIRS • Nitric Acid • Initial validation of limb nitric acid profiles

15. Validation Priorities (Next 12 Months) • INTEX-B (March-May, 2006) • Aircraft measurements for ozone, carbon monoxide and nitric acid with primary emphasis being the troposphere • Higher number of tropospheric profiles for comparisons • Maximize the number of ozonesonde launches coincident with Aura overpasses • Dedicated ozonesonde campaigns • Launches for a variety of geographic and seasonal conditions (improved statistics) • Special observations at ARM sites • MOZAIC Data Analysis for Ozone and Carbon Monoxide • Continue Analysis of AVE, PAVE data sets • Support of Field Campaigns: • AVE – Costa Rica (January-February, 2006) • MONA 2006 (Summer 2006) • Texas Air Quality Study/Gulf of Mexico Atmospheric Composition and Climate Study (Summer 2006)

16. INTEX-B • Provides an ideal opportunity for obtaining data sets for validation and science analysis. • Aircraft measurements for ozone, carbon monoxide and nitric acid with primary emphasis being the troposphere • Large number of tropospheric profiles for validation • TES can provide data global and regional coverage for areas of interest during INTEX-B

17. Extra

18. Documents • TES Validation Report • Avaiable by email, contact Greg Osterman (Gregory.Osterman@jpl.nasa.gov) • Soon available at TES External Website • Data Product Specification (DPS) • http://eosweb.larc.nasa.gov/PRODOCS/tes/DPS/ or • http://tes.jpl.nasa.gov/publications/documents/Data_Product_Spec_R7.doc • TES L1 Algorithm Theoretical Basis Document (ATBD) • Link • TES L2 ATBD v2.0 • Link

19. AVE 2006 – Costa Rica • Scanning-HIS measurements provide validation opportunities for TES L1B radiances • Maximize number of profiles made into the upper troposphere to maximize the utility of in situ ozone and carbon monoxide measurement • Maximize number of ozonesonde launches coincident with Aura overpasses

20. TES Data for PAVE Time Period • Limited Data Availability for PAVE • Two Step & Stare runs for February 3, 2005 • L1B Calibration issues caused problems with L2 data at low temperatures • We do not have a high confidence level in our retrievals poleward of 60° at this time • Updated calibration will improve the quality of the high latitude L2 retrievals

21. Validation Priorities (Next 12 Months) • Maximize the number of ozonesonde launches coincident with Aura overpasses • Dedicated ozonesonde campaigns • Launches for a variety of geographic and seasonal conditions (improved statistics) • Special observations at ARM sites • INTEX-B • Aircraft measurements for ozone, carbon monoxide and nitric acid with primary emphasis being the troposphere • Higher number of profiles for comparisons • MONA 2006 • Profiles from ozonesondes and lidars • Texas Air Quality Study/Gulf of Mexico Atmospheric Composition and Climate Study • Aircraft measurements in the troposphere, ship-based measurements and ozonesonde launches • MOZAIC Data Analysis for Ozone and Carbon Monoxide • Analysis of Scanning-HIS Data • Emphasis on retrievals of profiles for ozone and carbon monoxide

22. Validation Status for IndividualTES Data Products (v001) • L1B Radiances • Comparisons with Aqua-AIRS agree to better than 1K in brightness temperature • Similar results seen in comparisons of TES data with the aircraft instrument Scanning-HIS • Systematic radiance errors estimated at approximately 2% • Ozone • Generally good agreement with ozonesondes • Ozonesonde comparisons show a consistent bias toward larger ozone values in the upper troposphere • Ozone column comparisons with TOMS show similarly good results but with a 5% discrepancy toward higher values • Carbon Monoxide • Comparisons with Terra-MOPITT show retrievals agree to ~10% • Comparisons with profile data taken by the aircraft instrument Argus agree to within the estimated TES retrieval errors.

23. Validation Status for IndividualTES Data Products (v001) • Water Vapor • Comparisons of profiles with AIRS and aircraft instruments show good qualitative agreement • Comparisons with AIRS and AMSR-E show total column water vapor from TES is 10% dry • Profiles show most of the bias with AIRS in a layer between 700 and 900 hPa • Temperature • Initial comparisons with AIRS show agreement to within 2 K • Similar vertical structure in profiles is observed • Sea Surface Temperature (SST) • Preliminary results show excellent agreement to Reynolds Optimally Interpolated SST with overall bias of 0.07K and day/night temperatures fluctuating with a variance of 1.3 K about the weekly mean for Nov 4-16, ‘04 data • AIRS – TES comparison show high correlation with TES ~2K warmer overall than AIRS for Nov 4-14, ‘04 data

24. Definition of Different Labels for Validation Status • Beta -- Early release product, minimally validated and may still contain significant errors. This version of the data allows users to gain familiarity with data formats and how to properly use the data. The data is generally not appropriate as the basis for quantitative scientific publications. • Provisional -- Product quality may not be optimal and incremental product improvements are still occurring. General research community is encouraged to participate in the QA and validation of the product, but need to be aware that product validation and QA are ongoing. Users are urged to contact science team representatives prior to use of the data in publications. • Validated -- Formally validated product, although validation is still ongoing. Uncertainties are well defined, and products are ready for use in scientific publications, and by other agencies. There may be later improved versions of these products.

27. TES Global Survey with 2 nadir, 3 limb scans/sequence. Nadir scans are averaged (limb scans not shown) 14 Nov. 2004 TES Global Survey with 3 nadir scans/ sequence. Nadir scans are not averaged. No limb scans taken. 21 May 2005

28. INTEX-B • Provides an ideal opportunity for obtaining data sets for validation and science analysis. • Aircraft measurements for ozone, carbon monoxide and nitric acid with primary emphasis being the troposphere • Large number of tropospheric profiles for validation • TES can provide data global and regional coverage for areas of interest during INTEX-B