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Clear-column radiative closure during ACE-Asia: Comparison of multiwavelength extinction derived from particle size and composition with results from Sun photometry

Wang, J. and Flagan, R. C. and Seinfeld, J. H. and Jonsson, H. H. and Collins, D. R. and Russell, P. B. and Schmid, B. and Redemann, J. and Livingston, J. M. and Gao, S. and Hegg, D. A. and Welton, E. J. and Bates, D. (2002) Clear-column radiative closure during ACE-Asia: Comparison of multiwavelength extinction derived from particle size and composition with results from Sun photometry. Journal of Geophysical Research. Atmospheres, 107 (D23). Art. No. 4688. ISSN 2169-897X. https://resolver.caltech.edu/CaltechAUTHORS:20150818-101054502

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Abstract

From March to May 2001, aerosol size distributions and chemical compositions were measured using differential mobility analyzers (DMA), an aerodynamic particle sizer (APS), Micro-Orifice Uniform Deposit Impactors (MOUDI), and denuder samplers onboard the Twin Otter aircraft as part of the Aerosol Characterization Experiment (ACE)-Asia campaign. Of the 19 research flights, measurements on four flights that represented different aerosol characteristics are analyzed in detail. Clear-column radiative closure is studied by comparing aerosol extinctions predicted using in situ aerosol size distribution and chemical composition measurements to those derived from the 14-wavelength NASA Ames Airborne Tracking Sun photometer (AATS-14). In the boundary layer, pollution layers, and free troposphere with no significant mineral dust present, aerosol extinction closure was achieved within the estimated uncertainties over the full range of wavelengths of AATS-14. Aerosol extinctions predicted based on measured size distributions also reproduce the wavelength dependence derived from AATS-14 data. Considering all four flights, the best fit lines yield Predicted/Observed ratios in boundary and pollution layers of 0.97 ± 0.24 and 1.07 ± 0.08 at λ = 525 nm and 0.96 ± 0.21 and 1.08 ± 0.08 at λ = 1059 nm, respectively. In free troposphere dust layers, aerosol extinctions predicted from the measured size distributions were generally smaller than those derived from the AATS-14 data, with Predicted/Observed ratios of 0.65 ± 0.06 and 0.66 ± 0.05 at 525 and 1059 nm, respectively. A detailed analysis suggests that the discrepancy is likely a result of the lack of the knowledge of mineral dust shape as well as variations in aerosol extinction derived from AATS-14 data when viewing through horizontally inhomogeneous layers.


Item Type:Article
ORCID:
AuthorORCID
Flagan, R. C.0000-0001-5690-770X
Seinfeld, J. H.0000-0003-1344-4068
Jonsson, H. H.0000-0003-3043-1074
Gao, S.0000-0001-7427-6681
Additional Information:© 2002 American Geophysical Union. Received 19 April 2002; revised 23 July 2002; accepted 25 July 2002; published 5 December 2002. We thank Brian Mader, Jose Jimenez, and Roya Bahreini for sharing their data. This work was supported by National Science Foundation grant ATM-0001934, Office of Naval Research grants N00014-96-1-0119, N00014-01-F-0404, and N00014-97-1-0132, National Aeronautics and Space Administration Program codes 622-44-75-10 and 291-01-91-45, and National Oceanographic and Atmospheric Administration order NAO2AANRG0129.
Funders:
Funding AgencyGrant Number
NSFATM-0001934
Office of Naval Research (ONR)N00014-96-1-0119
Office of Naval Research (ONR)N00014-01-F-0404
Office of Naval Research (ONR)N00014-97-1-0132
NASA622-44-75-10
NASA291-01-91-45
National Oceanic and Atmospheric Administration (NOAA)NAO2AANRG0129
Subject Keywords:aerosol optical depth, ACE-Asia, Sun photometer
Issue or Number:D23
Classification Code:0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0360 Atmospheric Composition and Structure: Transmission and scattering of radiation; 0345 Atmospheric Composition and Structure: Pollution—urban and regional
Record Number:CaltechAUTHORS:20150818-101054502
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20150818-101054502
Official Citation:Wang, J., et al., Clear-column radiative closure during ACE-Asia: Comparison of multiwavelength extinction derived from particle size and composition with results from Sun photometry, J. Geophys. Res., 107(D23), 4688, doi:10.1029/2002JD002465, 2002.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:59696
Collection:CaltechAUTHORS
Deposited By: Irina Meininger
Deposited On:20 Aug 2015 19:54
Last Modified:09 Mar 2020 13:18

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