Atmos. Chem. Phys. Discuss., 11, 29003-29054, 2011
© Author(s) 2011. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Statistical evaluation of aerosol retrievals from AERONET using in-situ aircraft measurements
A. R. Esteve1, J. A. Ogren2, P. J. Sheridan2, E. Andrews2,3, B. N. Holben4, and M. P. Utrillas1
1Department of Earth Physics and Thermodynamics, University of Valencia, Valencia, Spain
2Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado, USA
3Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
4Goddard Space Flight Center, National Aeronautics and Space Administration, Greenbelt, Maryland, USA

Abstract. Aerosol optical properties were measured by NOAA's Airborne Aerosol Observatory over Bondville, Illinois, during more than two years using a light aircraft. Measured properties included total light scattering, backscattering, and absorption, while calculated parameters included aerosol optical depth (AOD), Ångström exponent, single-scattering albedo, hemispheric backscatter fraction, asymmetry parameter, and submicrometer mode fraction of scattering. The in-situ aircraft measurements are compared here with AERONET measurements and retrievals of the aerosol optical properties at the same location. The comparison reveals discrepancies between the aerosol properties retrieved from AERONET and from in-situ aircraft measurements. These discrepancies are smaller for the AOD, while the biggest discrepancies are for the single-scattering albedo, hemispheric backscatter fraction, and asymmetry parameter. Possible sources of discrepancy between the AOD measured by AERONET and the one calculated from the in-situ aircraft measurements are investigated. The largest portion of the AOD discrepancy is likely due to an incorrect adjustment to ambient RH of the scattering coefficient. Another significant part (along with uncertain nephelometer truncation corrections) may come from the possibility that there might be less aerosol below the lowest flight altitude or that the aircraft inlet excludes aerosol particles larger than 5–7 μm diameter.

Citation: Esteve, A. R., Ogren, J. A., Sheridan, P. J., Andrews, E., Holben, B. N., and Utrillas, M. P.: Statistical evaluation of aerosol retrievals from AERONET using in-situ aircraft measurements, Atmos. Chem. Phys. Discuss., 11, 29003-29054, doi:10.5194/acpd-11-29003-2011, 2011.
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