1. Explore. Discover. Understand. AIR-BROADENED LINE WIDTHS AND SHIFTS IN THE ν 3 BAND OF 16 O 3 AT TEMPERATURES BETWEEN 160 AND 300 K M. A. H. SMITH and C. P. RINSLAND NASA Langley Research Center, Hampton, VA 23681-2199 U.S.A. V. MALATHY DEVI and D. CHRIS BENNER The College of William and Mary, Williamsburg, VA 23187-8795 U.S.A. A.M. COX New Horizons Governor’s School for Science and Technology, Hampton, VA 23666 and Poquoson High School, Poquoson, VA 23662 U.S.A.

2. Explore. Discover. Understand. Good vs. Bad Ozone “Good” Ozone in the Stratosphere (10 – 40 km) Produced from photodissociation of O 2 molecules Peak O 3 concentrations at ~ 25 km Protects life from harmful shortwave UV radiation Destroyed by compounds such as CFCs released into the atmosphere Significant depletion contributes to cooling of the stratosphere  “Bad” Ozone in the Troposphere (0 – 10 km)  Produced in photochemical smog  Toxic to animals (including humans) when inhaled  Causes damage to plants  A greenhouse gas in the upper troposphere  Reacts to cleanse the troposphere of some pollutants

3. Explore. Discover. Understand. Tropospheric Ozone Measured from Space Since 1978 the Total Ozone Mapping Spectrometer (TOMS) instruments have been measuring global ozone levels from a variety of satellites. Instruments aboard the Aura satellite launched in 2004 are continuing the long term monitoring of ozone. Learn more about tropospheric ozone at http://earthobservatory.nasa.gov/

4. Explore. Discover. Understand. Global Average Temperature Profile Tropopause temperatures vary with latitude and season, and are typically below 195 K in the tropics.

5. Explore. Discover. Understand. Hurricanes and Ozone Ozone column measurements collected over Hurricane Erin on September 12, 2001 by the TOMS instrument on NASA’s Earth Probe satellite In the eye, where air from the stratosphere is transported downward, ozone concentrations are elevated (yellow and green). The core is surrounded by an area of much lower ozone concentrations (purple and blue) due to ozone-poor surface air being transported upward by strong thunderstorms. Dropping ozone levels around the eye may be sign that a storm is strengthening. From http://earthobservatory.nasa.gov/

6. Explore. Discover. Understand. Spectra Used for Ozone Fits in the ν 3 Band Band pass 1 = 500-1400 cm-1; Band pass 2 = 800-1400 cm-1 All spectra were recorded using the McMath-Pierce FTS with KCl beam splitter, 8 mm aperture, and He-cooled As:Si detectors. February 1996 spectra were used in the intensity study published in JGR (Smith et al., 2001). May 1998 spectra were recorded using a single detector.

7. Explore. Discover. Understand. Example of a Measured Spectrum 50-cm cell 0.3 % O 3 in air p = 86.2 torr T = 213 K Resolution = 0.0052 cm-1 ▲Red triangles mark lines for which parameters were determined.

8. Explore. Discover. Understand. Multispectrum Fitting Strategy 1)Four low-pressure spectra for which concentrations were determined by UV absorption (254 nm) were fit together first to obtain absolute line intensities. 2)Intensities were fixed to these retrieved values for subsequent fitting of air-broadened spectra. 3)Room-temperature air-broadened spectra were added to the fit first, followed by the lower-temperature spectra down to 213 K. 4)Noisy spectra from 186 to 160K were added to the fit with low weights due to relatively poor Signal-to-Noise. 5)Parameters have been determined for 41 P-branch lines in the spectral region 1016 – 1025 cm -1 (J˝ = 15 – 26, K a ˝ = 0 – 11).

9. Explore. Discover. Understand. Results: Intensities

10. Explore. Discover. Understand. Results: Broadening Coefficients

11. Explore. Discover. Understand. Results: Broadening Temperature Dependence Exponents

12. Explore. Discover. Understand. Results: Pressure-Induced Line Shifts

13. Explore. Discover. Understand. Results: Temperature Dependences of Pressure-Induced Line Shifts

14. Explore. Discover. Understand. Comparison with the Other Fundamental Bands Measured values are from Present Work, Malathy Devi et al. (1997) and Smith et al. (1997). Calculated values are based on empirical formulas given by Wagner et al. (2002).

15. Explore. Discover. Understand. Comparison with Overtone Band

16. Explore. Discover. Understand. Summary Intensities, air-broadening and shift parameters have been determined for 41 ν 3 P-branch lines with J˝ = 15 – 26 from spectra recorded at temperatures from 160 K to 300 K. Intensities retrieved with 2005 version of the multispectrum fitting program are identical to those retrieved from the same spectra for the 2001 study. Air-broadening coefficients agree within 5% or better with measurements in the ν 1, ν 2, and 3ν 3 bands and with HITRAN 2004. Air-shift coefficients agree within error bars with measurements in the ν 1 and ν 2 bands and with HITRAN 2004. Vibrational dependence of the air-shift coefficients is apparent between the ν 3 and 3ν 3 bands. Temperature dependence exponents for air-broadening are 5 to 25% smaller than HITRAN 2004 values. The measured values generally decrease with J˝, while the HITRAN values increase with J˝. More research is needed!