"Clear-Column Radiative Closure During ACE-Asia: Comparison of Multiwav" by J. Wang, Richard C. Flagan et al.

Chemistry and Physics Faculty Articles

Title

Clear-Column Radiative Closure During ACE-Asia: Comparison of Multiwavelength Extinction Derived from Particle Size and Composition with Results from Sun Photometry

Authors

J. Wang, California Institute of Technology
Richard C. Flagan, California Institute of Technology
John H. Seinfeld, California Institute of Technology
Haflidi Jonsson, Naval Postgraduate School
D. R. Collins, Texas A & M University - College Station
P. B. Russell, NASA Ames Research Center
Beat Schmid, Bay Area Environmental Research Institute
Jens Redemann, Bay Area Environmental Research Institute
J. M. Livingston, SRI International
Song Gao, University of Washington - Seattle CampusFollow
Dean A. Hegg, University of Washington - Seattle Campus
E. J. Welton, NASA Goddard Earth Sciences and Technology Center

Document Type

Article

Publication Date

12-16-2002

Publication Title

Journal of Geophysical Research: Atmospheres

Keywords

Aerosol optical depth, ACE-Asia, Sun photometer

ISSN

2169-897X

Volume

107

Issue/No.

D23

First Page

AAC 7-1

Last Page

AAC 7-22

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.

Comments

Additional Comments

4688

NSUWorks Citation

Wang, J., Flagan, R. C., Seinfeld, J. H., Jonsson, H., Collins, D. R., Russell, P. B., Schmid, B., Redemann, J., Livingston, J. M., Gao, S., Hegg, D. A., & Welton, E. J. (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), AAC 7-1 - AAC 7-22. https://doi.org/10.1029/2002JD002465. Retrieved from https://nsuworks.nova.edu/cnso_chemphys_facarticles/144

DOI

10.1029/2002JD002465

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