National Aeronautics and Space Administration
AIRS THE ATMOSPHERIC INFRARED SOUNDER ON NASA’S AQUA SATELLITE
Global carbon dioxide data of Earth’s mid-troposphere The first release of a 7-year global carbon dioxide data set based solely on observations
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About the Instrument
US Standard Atmosphere CO2 390 ppm Stratospheric Mid-tropospheric Near-surface
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Pressure, hPa
The Atmospheric Infrared Sounder, AIRS, was launched aboard the Aqua spacecraft in 2002 as part of NASA’s Earth Observing System Afternoon Constellation of satellites known as the “A-Train.” Key features of the AIRS instrument are: • 2378 hyperspectral infrared channels • High accuracy, sensitivity, and stability • Global daily coverage • Sensitive to carbon dioxide in 3 layers (only mid-troposphere data available at this time)
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The AIRS Carbon Dioxide Product
AIRS reports the daytime and nighttime global distribution of carbon dioxide in the mid-troposphere at a nadir resolution of 90 km x 90 km. The high spectral resolution and stability of AIRS allows a measurement accuracy between 1.5 ppm and 2 ppm, making it ideal for mapping the distribution and transport of carbon dioxide in the free troposphere. AIRS CO2 retrievals have been validated by comparison with: • Airborne flask measurements by CONTRAIL • Airborne CO2 profile measurements • Upward-looking FTIR systems
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AIRS Sensitivity to CO2 with Altitude
Monthly average of carbon dioxide in the middle troposphere, made with AIRS data retrieved in July 2003.
7-day averages of AIRS retrievals: Latitude = +25° ± 5° Longitude = 143° ± 5° CONTRAIL individual flask measurements: Latitude = +25° ± 5° 390 385 CO2, ppm
The hyperspectral data from AIRS have been used to produce global maps of carbon dioxide and other trace gases including ozone, methane, and carbon monoxide. These data are providing important constraints on modeling the global distribution and transport of these gases around the world. The AIRS carbon dioxide data set currently consists of: • CO2 in the mid-troposphere • Level 2 data (individual soundings) • 18,000 soundings per day • Global daily coverage, latitude range 60 S to 90 N • Level 3 data in daily, multi-day, and calendar monthly at a spatial resolution of 2 deg latitude by 2.5 deg longitude • Better than 2 ppm accuracy
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AIRS CONTRAIL
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7-day averages of AIRS retrievals: Latitude = +25° ± 5° Longitude = 150° ± 5° CONTRAIL individual flask measurements: Latitude = –25° ± 5° 390 385 CO2, ppm
AIRS has provided the first satellite retrieval of midtropospheric CO2 under cloudy conditions, without the use of a priori information from models. AIRS retrievals use cloud-cleared thermal IR radiance spectra in the 15 micron band with an accuracy better than 2 ppm.
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AIRS CONTRAIL
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Rate of Growth: AIRS = 1.98 ± 0.05 ppm/year (30°S to 30°N) CONTRAIL = 2.01 ± 0.04 ppm/year
Comparison of V2 AIRS CO2 and CONTRAIL (Matsueda) Airborne Flask Measurements
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AIRS THE ATMOSPHERIC INFRARED SOUNDER ON NASA’S AQUA SATELLITE Significant Findings from AIRS Data •
CO2 is not homogeneous in the mid-troposphere; previously it was thought to be well-mixed.
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The distribution of CO2 in the mid-troposphere is strongly influenced by large-scale circulations such as the mid-latitude jet streams and by synoptic weather systems, most notably in the summer hemisphere.
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There are significant differences between simulated and observed CO2 abundance outside of the tropics, raising questions about the transport pathways between the lower and upper troposphere in current models.
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Large-scale intraseasonal and interannual anomalies of the order of ~1 ppm in tropical mid-tropospheric CO2 indicate large-scale vertical transport of carbon dioxide and correlates well with with the MaddenJulian oscillation (MJO), El Niño-Southern Oscillation (ENSO) and the Tropical Biennial Oscillation (TBO).
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AIRS data suggest strong zonal transport of CO2 in the free troposphere is strongly zonal and seasonally variable. This distribution and variability is not present in models. The complexity of the carbon cycle and three-dimensional transport of trace constituents in the southern hemisphere as well as the transport of CO2 between the hemispheres require further study.
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Monthly average atmospheric carbon dioxide concentration for July 2009 = 387 ppm. Measurement recorded at Mauna Loa Observatory (Scripps/NOAA/ESRL).
Carbon Dioxide in the Mid-Troposphere, 2009.
AIRS data products are free and are available to the science community and general public How to get AIRS CARBON dioxide data
Key Papers Liu, J., I. Fung, E. Kalnay, J-S Kang, E. T. Olsen, and L. Chen (2012), “Simultaneous Assimilation of AIRS XCO2 and Meteorological Observations in a Carbon Climate Model with an Ensemble Kalman Filter,” J. Geophys. Res., doi:1029/2011JD016642. Wang, J., X. Jiang, M. T. Chahine, M.-C. Liang, E. T. Olsen, L. L. Chen, S. J. Licata, T. S. Pagano, and Y. L. Yung (2011), “The Influence of Tropospheric Biennial Oscillation on Mid-Tropospheric CO2,” Geophys. Res. Lett., 38, L20805, doi:10.1029/2011GL049288. Li, K.-F., B. Tian, D. E. Waliser, and Y. L. Yung (2010), “Mid-Tropospheric CO2 Variability Driven by the Madden–Julian Oscillation,” PNAS, 107 (45) 19171-19175, doi:10.1073/pnas.1008222107. 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. Engelen, R. J., S. Serrar, and F. Chevallier (2009), “Four-Dimensional Data Assimilation of Atmospheric CO2 Using AIRS Observations,” J. Geophys. Res., 114, D03303, doi:10.1029/2008JD010739. Chahine, M. T. et al. (2008), “Satellite Remote Sounding of Mid-Tropospheric CO2,” Geophys. Res. Lett., 35, September, doi:10.1029/2008GL035022. Maddy, E. S., C. D. Barnet, M. Goldberg, C. Sweeney, and X. Liu (2008), “CO2 Retrievals from the Atmospheric Infrared Sounder: Methodology and Validation,” J. Geophys. Res.–Atmospheres, 113, D11, D11105.
The Goddard Earth Sciences Data and Information Services Center (GES-DISC) at Goddard Space Flight Center serves as the central facility for the processing, archiving, and distribution of EOS Aqua data. Access to AIRS near-real-time-data, the AIRS data FTP server, the Giovanni browse tool, and other data access methods can be found here: http://disc.sci.gsfc.nasa.gov/AIRS/data-holdings Resources and help
The AIRS data support page at the GES-DISC includes documentation, data product descriptions and software tools: http://disc.sci.gsfc.nasa.gov/AIRS/ The AIRS public website contains information, images, and contact information: http://airs.jpl.nasa.gov ASK AIRS is an online form for questions about AIRS data and products: http://airs.jpl.nasa.gov/AskAirs/ Contact Information
For further inquiries about AIRS data and products, please contact: Edward Olsen, AIRS Data Users Lead 818.354.7604 edward.t.olsen@jpl.nasa.gov The Jet Propulsion Laboratory, California Institute of Technology, manages the AIRS instrument suite for the National Aeronautics and Space Administration.
Strow, L. Larrabee and Scott E. Hannon (2008), “A 4-year Zonal Climatology of Lower Tropospheric CO2 Derived from Ocean-Only Atmospheric Infrared Sounder Observations,” J. Geophys. Res., doi:10.1029/2007JD009713. Tiwari, Y. K., M. Gloor, R. J. Engelen, F. Chevallier, C. Rödenbeck, S. Körner, P. Peylin, B. H. Braswell, and M. Heimann (2006), “Comparing CO2 Retrieved from Atmospheric Infrared Sounder with Model Predictions: Implications for Constraining Surface Fluxes and Lower-to-Upper Troposphere Transport,” J. Geophys. Res., 111, D17106, doi:10.1029/2005JD006681. Chahine M., C. Barnet, E. T. Olsen, L. Chen, and E. Maddy (2005), “On the Determination of Atmospheric Minor Gases by the Method of Vanishing Partial Derivatives with Application to CO2,” Geophys. Res. Lett., 32, L22803, doi:10.1029/2005GL024165.
National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California www.nasa.gov JPL 400-1389 Rev. 1 3/12