Atmospheric Chemistry Experiment, ACE: Status and Spectroscopic Issues

1. Atmospheric Chemistry Experiment, ACE: Status and Spectroscopic Issues • Peter Bernath, Nick Allen, Gonzalo Gonzalez Abad, Jeremy Harrison, Alex Brown, and Keith Tereszchuk • (University of York, UK) • Chris Boone • (University of Waterloo, Canada)

2. Topics HCN in Asian Monsoon ACE solar & atmospheric atlases Organics: ethane, propane, acetone, methanol, acetaldehyde, acetonitrile (etc.) Halogenated gases

3. ACE Satellite http://www.ace.uwaterloo.ca/ Bernath et al., GRL, 32, L15S01 (2005)

4. Solar Occultation Advantages: Radiance of sun gives higher S/N than emission Limb view gives longer path length ~500 km (lower detection limits) than nadir “Self-calibrating” so excellent long-term accuracy and precision Disadvantages: Modest global coverage Samples only free troposphere

5. Optical Layout (ABB-Bomem)

6. Atmospheric Dynamics: Asian Summer Monsoon Anticyclone At 13.5 km in altitude, HCN is high over Tibet because of rapid lofting of polluted air from India and China during summer; it is lower over the Pacific Ocean because of deposition and destruction in the ocean. Randel et al., Science 328, 611 (2010).

8. Fox News

10. ACE Solar Spectrum CH, NH, OH OH CO Δv=2 Hase et al. JQSRT 111, 521 (2010) OH: Bernath & Colin, JMS 257, 20 (2009) & HITRAN2008; NH: Ram & Bernath JMS 260, 115 (2010) CO, Δv=1 Used in Leicester for IASI CO retrievals ACE solar spectrum (F. Hase): 224782 spectra added, improvement over ATMOS, no telluric lines, but 0.02 cm-1 vs 0.01 cm-1 resolution (resolution largely determined by width of solar lines) and 750-4400 cm-1 vs 600-4800 cm-1.

11. CH Bands in ACE Solar Spectrum CH: Colin & Bernath, JMS (submitted)

12. (8-12 km, MLW) ACE Atmospheric Atlases • Five average atmospheres: Tropics, Mid Latitude Summer (MLS), MLW, Arctic Summer (AS), AW • For each atmosphere a plot for troposphere, stratosphere, mesosphere, lower thermosphere (plus digital data for all tangent heights) • Spectra have now been wavenumber calibrated and apodized R. Hughes, in progress

13. VOCs and Air Quality Volatile Organic Compounds (VOCs) lead to the production of tropospheric ozone, a pollutant.

14. Molecular Spectroscopy Facility at Rutherford Appleton Lab Bruker IFS 125 HR, with short path and long path coolable cells

15. Ethane, Propane and Acetone (3 micron region) Harrison et al., JQSRT 111, 357-363 (2010) Harrison & Bernath, JQSRT 111, 1282 (2010) Harrison et al., JQSRT; two papers LW (in prep.) and SW (submitted) regions

16. Methanol, Acetaldehyde, Acetonitrile (3 micron region) To be recorded at RAL, July 2010 (Spectra recorded at York) Tereszchuk & Bernath, JQSRT (in preparation) Time requested at RAL

17. CH4 Interferes with Hydrocarbons near 3.3 µm: Non-Voigt lineshapes needed Harrison & Bernath, JQSRT 111, 1282 (2010) CH4 lines 8-12 km tropical average

18. ACE-FTS spectrum near 25 km (ss11613) Failing to account for CH4 line mixing affects the apparent baseline near the HCl line, generating errors when this line is employed in HCl retrievals. Residuals for all measurements between 10 and 35 km on a common plot. Line mixing parameters for lines in the CH43P(9) manifold were derived from the ACE-FTS spectra using the Rosenkranz first order approximation.

19. Halogen Budget and Trends Retrievals v. 3: CFC-11, CFC-12 , CFC-113, HCFC-22, HCFC-141b, HCFC-142b, CCl4, CH3Cl, CF4, SF6, (HFC-134a), F2CO, ClFCO, Cl2CO, HCl, HF, ClONO2, (ClO)

20. CFC-12 HCFC-142b SF6 HCFC-22

21. Search for Earth-like Extrasolar Planets Recent launch of NASA’s Kepler mission will lead to the detection of other Earth-like planets.