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Xun Jiang1, Moustafa Chahine2, Edward Olsen2, Luke Chen2, and Yuk Yung3

Variability of Tropospheric & Stratospheric CO2 From the

Atmospheric Infrared Sounder

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

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Overview

Motivation

Data

Variability of Mid-tropospheric CO2

1. Trend & Seasonal Cycle2. ENSO

Stratospheric CO2

Conclusions

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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

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Data – AIRS Mid-Trop CO2 Product

• 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

AIRS Mid-Trop Contribution Function

314 hPa

478 hPa

AIRS Mid-tropospheric CO2 Sensitivity Peak: 500-300 hPa (depending upon latitude)Chahine et al. [2005; 2008]

GEOS-Chem

AIRS

Comparison Between AIRS CO2 With Model Simulation

JULY 2003 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].

AIRS Data are 7-day averages; CONTRAIL data are individual measurementsOlsen et al., manuscript in preparation [2010]

CO2 Trend AIRS: 1.96 ± 0.08 ppmCONTRAIL: 1.96 ± 0.14 ppm

CO2 Trend AIRS: 2.07 ± 0.03 ppmCONTRAIL: 1.98 ± 0.05 ppm

Lat: +25º ± 5ºLon: 143º ± 5º

Lat: -25º ± 5ºLon: 150º ± 5º

Trend and Seasonal Cycle of AIRS CO2

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Influence of El Niño/La Niña on AIRS CO2

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Influence of El Niño/La Niña on AIRS CO2

El Niño: Feb 2005

La Niña: Feb 2008

El Niño: Feb 2010

Influences of El Niño on Mid-Trop CO2 From AIRS and MOZART-2

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TOP: AIRS detrended and deseasonalized CO2

anomaly averaged for 11 El Nino months

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

MIDDLE: AIRS detrended and deseasonalized CO2

anomaly averaged for 17 La Nina months

BOTTOM: AIRS CO2 anomaly difference (El Nino – La Nina) (Consistent with change in Walker Circulation)

+1.56 ppm

+1.56 ppm

+1.56 ppm

-1.00 ppm

-1.00 ppm

-1.00 ppm

TOP: MOZART-2 CO2 anomaly during El Nino

MIDDLE: MOZART-2 CO2 anomaly during La Nina

BOTTOM: MOZART-2 CO2 Difference (El Nino – La Nina) (signal is smaller than observed by AIRS)

NOTE: MOZART-2 results are preliminary. The boundary conditionis a climatology and does not include interannual variability

+0.95 ppm

+0.59 ppm

+0.95 ppm

-0.54 ppm

-0.33 ppm

-1.12 ppm

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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.

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Data – AIRS Stratospheric CO2 Product

AIRS Stratospheric CO2 Sensitivity Peak: 20 hPa

23.5 hPa

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 GEOS-Chem3-D IMATCH

3-D MOZART-2 3-D Carbon Tracker

Color Bar Range: -5 to +5 ppm

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.

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Thank you!