1. ACE Linelist Needs for the Atmospheric Chemistry Experiment Chris Boone and Peter Bernath Univ. of Waterloo, Waterloo, Ontario, Canada HITRAN 2006 Conference June 27, 2006

2. ACE Atmospheric Chemistry Experiment n Satellite mission for remote sensing of the Earth’s atmosphere, with a primary focus on Arctic ozone n Developed by the Canadian Space Agency n Launched August 2003, science operations began February 2004 n Operating well, no major problems yet. n Currently funded through April 2007.

3. ACE Solar Occultation

4. ACE Instruments n Infrared Fourier Transform Spectrometer operating between 2 and 13 microns with a resolution of 0.02 cm -1 (  25 cm MPD) n 2-channel visible/near infrared Imagers, operating at 0.525 and 1.02 microns n UV / Visible spectrometer (MAESTRO) 0.285 to 1.03 microns, resolution ~1-2 nm n Suntracker n Startracker

5. ACE ACE-FTS (ABB-Bomem) Interferometer-sideInput optics-side

6. ACE Excellent SNR Performance Note: after detector decontamination

7. ACE H2OH2OH2OH2O HITRAN 2004: 7.746e-24, 0.06954 HITRAN 2006: 7.746e-24, 0.0768 DLR: 7.75e-24, 0.0768

8. ACE Occultation with less water The H 2 O lineshape problems only occur when working with high water levels (but not high enough for self-broadening parameters to be significant). When one has pressure broadening with lower water levels, the recently determined H 2 O broadening parameters give improved residuals.

9. ACE H 2 O lineshape n Major problems at low altitudes, makes it difficult to perform some retrievals in the lower troposphere. n Voigt lineshape inappropriate? n Variations along the line of sight playing some role? n HITRAN 2006 H 2 O parameters seem to improve fitting (  2 decreases by 4 - 10%)

10. ACE CFC-113 Bad water residual Even in the low water case, large residuals from water lines complicate retrievals that need to go deep into the troposphere

11. ACE Version 2.2 Ozone n Validation results: ACE-FTS ozone ~5% low near the profile peak compared to other measurements. n Microwindows in two wavenumber regions: “Cleaner” region given greater weight and pulled the fit. Large residuals in the other region (compared to SNR)

12. ACE

13. O3O3O3O3 ~3-4% increase between 15 and 50 km, leading to better agreement with other measurements.

14. ACE O 3 parameters n Likely a ~4% discrepancy between the ozone line strength parameters in the two wavenumber regions. n Results from the lower wavenumber region agree better with validation data; suggests a problem with the higher wavenumbers.

15. ACE HNO 3 Improved consistency with the HITRAN 2004 linelist (compared to previous versions), but there remains a significant discrepancy between the two wavenumber regions.

16. ACE N2N2N2N2 Improved N 2 parameters from Aaron Goldman (see his poster for more details).

17. ACE C2H6C2H6C2H6C2H6 Q-branch Unidentified spectral features in C 2 H 6 fitting microwindow

18. ACE C2H6C2H6C2H6C2H6 C2H6 Q-branches returned to the linelist, but of poorer quality than the feature near 2976.8 cm -1

19. ACE COClF Lab spectrum from Kitt Peak, courtesy of Curtis Rinsland

20. ACE COClF in ACE spectra ? ?

21. ACE Sparse Cross-Section Data n HNO 4 : 1 cross-section file, difficult to perform a retrieval n PAN: 2 files (2 different frequency regions) n HCFC-142b: 3 measurements (253, 270, and 287 K). Ideally, the data would go lower in T for atmospheric work n CH 3 CN: 3 measurements (276.1, 298.7, and 324.1 K). Again, ideally lower T.

22. ACE Conclusions n Strong push into troposphere: –Improved water –CFCs and HCFCs –Hydrocarbons (e.g., acetone, propane,…) n The listed errors on CO 2 line intensities are 2-5%. The accuracy of everything ties back to CO 2 (through pressure and temperature). It would be nice to have smaller errors.