1. National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California Atmospheric Infrared Sounder 1 1 Department of Earth & Atmospheric Sciences, Univ. of Houston 2 Science Division, Jet Propulsion Laboratory, Caltech 3 Division of Geological & Planetary Sciences, Caltech NASA Sounding Science Meeting, May 4-7, 2009 Xun Jiang 1, Moustafa Chahine 2, Edward Olsen 2, Luke Chen 2, and Yuk Yung 3 Seasonal and Interannual Variability of AIRS CO 2

2. National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California Atmospheric Infrared Sounder 2 Overview  Data  Seasonal Cycle of AIRS CO 2  Interannual Variability of AIRS CO 2

3. National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California Atmospheric Infrared Sounder 3 Data  AIRS CO 2 Sensitivity Peak: 500-300 hPa Chahine et al. [2005; 2008]  CO 2 aircraft data from CONTRAIL Matsueda et al. [2002]

4. Comparison Between AIRS CO 2 with Matsueda Aircraft Data Lat: 25º ± 5º; Lon: 143º ± 5º ● Matsueda CO 2 aircraft data (8-13km) —— AIRS CO 2 Lat: -25º ± 5º; Lon: 150º ± 5º 25 N 25 S

5. CO 2 Seasonal Cycle 25 N 25 S —— Matsueda CO 2 7-day Average —— AIRS CO 2 7-day Average

6. Jan 2003 Apr 2003 Jul 2003 Oct 2003 364.0 373.0 368.5 377.5 382.0 CO2 (ppm) Black Contours: 500 hPa Geopotential Height AIRS CO 2 Seasonal Cycle

7. National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California Atmospheric Infrared Sounder 7 Overview  Data  Seasonal Cycle of AIRS CO 2  Interannual Variability of AIRS CO 2

8. National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California Atmospheric Infrared Sounder Influence of El Niño/La Niña on AIRS CO 2 El Niño: Feb 2005 La Niña: Feb 2008

9. National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California Atmospheric Infrared Sounder La Niña Phase AIRS Detrended CO 2 in Feb 2008 Influence of El Niño/La Niña on AIRS CO 2

10. National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California Atmospheric Infrared Sounder El Niño Phase AIRS Detrended CO 2 in Feb 2005 Influence of El Niño/La Niña on AIRS CO 2

11. National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California Atmospheric Infrared Sounder El Niño - La Niña AIRS CO 2 Difference (Feb 2005 - Feb 2008) Influence of El Niño/La Niña on AIRS CO 2

12. National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California Atmospheric Infrared Sounder Detrended AIRS CO 2 from Nov to Apr at 60N - 90N (Black) Detrended Arctic Oscillation Index from Nov to Apr (Red) Correlation Coefficient = -0.74 AIRS CO 2 in the Northern Hemisphere

13. National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California Atmospheric Infrared Sounder AIRS CO 2 averaged in 2005 and 2007 Positive AO index; Strong Vortex AIRS CO 2 in the NH

14. National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California Atmospheric Infrared Sounder AIRS CO 2 averaged in 2006 and 2008 Negative AO index; Weak Vortex AIRS CO 2 in the NH

15. National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California Atmospheric Infrared Sounder AIRS CO 2 in the NH AIRS CO 2 Difference Strong Vortex - Weak Vortex

16. Conclusions  The seasonal cycle of AIRS middle tropospheric CO 2 agrees reasonably well with in situ aircraft observations of CO 2.  During El Niño year, there are more CO 2 in the central Pacific and less CO 2 in the western Pacific.  CO 2 at high latitudes correlate well with the strength of the polar vortex in the winter season. References: Chahine et al., GRL, doi:2005GL024165, 2005. Chahine et al., GRL, doi:2008GL035022, 2008. Jiang et al., GBC, In Press, 2008. Olsen et al., Submitted to JGR, 2009.

17. National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California Atmospheric Infrared Sounder 17 Thank you!