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Variability of Tropospheric & Stratospheric CO 2 From the Atmospheric Infrared Sounder. Xun Jiang 1 , Moustafa Chahine 2 , Edward Olsen 2 , Luke Chen 2 , and Yuk Yung 3. 1 Department of Earth & Atmospheric Sciences, Univ. of Houston 2 Science Division, Jet Propulsion Laboratory, Caltech
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Variability of Tropospheric & Stratospheric CO2 From the Atmospheric Infrared Sounder Xun Jiang1, Moustafa Chahine2, Edward Olsen2,Luke Chen2, and Yuk Yung3 1 Department of Earth & Atmospheric Sciences, Univ. of Houston 2 Science Division, Jet Propulsion Laboratory, Caltech 3 Division of Geological & Planetary Sciences, Caltech AGU Fall Meeting, Dec 13-17, 2010 1
Overview • Motivation • Data • Variability of Mid-tropospheric CO2 • Trend & Seasonal Cycle • ENSO • Stratospheric CO2 • Conclusions 2
Motivation • Improve understanding of CO2 variability and its effect on the global climate change using satellite data • Investigate how natural variability (e.g., ENSO) influence the global CO2 • Improve CO2 simulations from chemistry-transport models in the future 3
Data – AIRS Mid-Trop CO2 Product AIRS Mid-Trop Contribution Function • AIRS Mid-tropospheric CO2 • Sensitivity Peak: 500-300 hPa (depending upon latitude) • Chahine et al. [2005; 2008] 314 hPa 478 hPa • The AIRS Mid-Trop Contribution Function is a measure of the contribution of an atmospheric layer to the TOA radiance used in the AIRS CO2 retrieval 4
Comparison Between AIRS CO2 With Model Simulation JULY 2003 AIRS • Significant spatiotemporal variability in the AIRS CO2, which is supported by the aircraft observations [Chahine et al., GRL 2008]. • Convective vertical transport flux is important for correct simulation of mid-tropospheric CO2 [Jiang et al., GBC 2008]. GEOS-Chem
Trend and Seasonal Cycle of AIRS CO2 CO2 Trend AIRS: 1.96 ± 0.08 ppm CONTRAIL: 1.96 ± 0.14 ppm Lat: +25º ± 5ºLon: 143º ± 5º CO2 Trend AIRS: 2.07 ± 0.03 ppm CONTRAIL: 1.98 ± 0.05 ppm Lat: -25º ± 5ºLon: 150º ± 5º AIRS Data are 7-day averages; CONTRAIL data are individual measurements Olsen et al., manuscript in preparation [2010]
Influence of El Niño/La Niña on AIRS CO2 La Niña: Feb 2008 El Niño: Feb 2005 El Niño: Feb 2010
Influences of El Niño on Mid-Trop CO2 From AIRS and MOZART-2 +0.95 ppm +1.56 ppm -0.54 ppm -1.00 ppm +0.59 ppm +1.56 ppm -0.33 ppm -1.00 ppm +0.95 ppm +1.56 ppm -1.12 ppm -1.00 ppm TOP: MOZART-2 CO2 anomaly during El Nino TOP: AIRS detrended and deseasonalized CO2 anomaly averaged for 11 El Nino months MIDDLE: MOZART-2 CO2 anomaly during La Nina MIDDLE: AIRS detrended and deseasonalized CO2 anomaly averaged for 17 La Nina months BOTTOM: MOZART-2 CO2 Difference (El Nino – La Nina) (signal is smaller than observed by AIRS) BOTTOM: AIRS CO2 anomaly difference (El Nino – La Nina) (Consistent with change in Walker Circulation) Jiang, X., M. T. Chahine, E. T. Olsen, L. L. Chen, and Y. L. Yung (2010), Interannual variability of mid-tropospheric CO2 from Atmospheric Infrared Sounder, Geophys. Res. Lett., 37, L13801, doi:10.1029/2010GL042823 NOTE: MOZART-2 results are preliminary. The boundary conditionis a climatology and does not include interannual variability
Influence of El Niño/La Niña on AIRS CO2 Multiple regression method is applied to the AIRS CO2 data. We decompose CO2 concentrations to trend, annual cycle, semi-annual cycle and ENSO signal.
Data – AIRS Stratospheric CO2 Product • AIRS Stratospheric CO2 • Sensitivity Peak: 20 hPa 23.5 hPa 11
AIRS Stratospheric CO2(CO2 after subtracting <CO2> for |lat| ≤ 4 °) Jan 2003 Color Bar Range: -15 to +15 ppm
Stratospheric CO2 From Models(CO2 after subtracting <CO2> for |lat| ≤ 4 °) 3-D IMATCH 3-D GEOS-Chem Color Bar Range: -5 to +5 ppm 3-D MOZART-2 3-D Carbon Tracker
Conclusions • Significant spatiotemporal variability in the AIRS CO2. • Trend and seasonal cycle of AIRS CO2 agree well with those from CONTRAIL CO2. • Mid-tropospheric AIRS CO2 is modulated by the natural variability (e.g. El Niño). • AIRS stratospheric CO2 offer a new opportunity to constrain the models in the stratosphere. References: Chahine et al., GRL, doi:2005GL024165, 2005. Chahine et al., GRL, doi:2008GL035022, 2008. Jiang et al., GBC, doi:2008GL035022, 2008. Jiang et al., GRL, doi:2010GL042823, 2010. Olsen et al., Manuscript In Preparation, 2010.
Thank you! 15