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INDOEX aerosol: A comparison and summary of chemical, microphysical, and optical properties observed from land, ship, and aircraft

Clarke, A. D. and Howell, S. and Quinn, P. K. and Bates, T. S. and Ogren, J. A. and Andrews, E. and Jefferson, A. and Massling, A. and Mayol-Bracero, O. and Maring, H. and Savoie, D. and Cass, G. (2002) INDOEX aerosol: A comparison and summary of chemical, microphysical, and optical properties observed from land, ship, and aircraft. Journal of Geophysical Research D, 107 (D19). Art. No. 8033. ISSN 0148-0227. doi:10.1029/2001JD000572.

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The Indian Ocean Experiment (INDOEX) measurements on land, sea, and in the air were designed to provide complementary assessment of chemical, physical, and optical properties of the haze aerosol over the Indian Ocean. Differences in platform requirements and objectives resulted in diverse techniques, measurements, and analyses being employed. In order to best interpret the properties of the INDOEX aerosol, comparisons of data by platform, air mass origin, and light scattering intensity were undertaken. These revealed significant variability in platform averages of aerosol extensive properties (e.g., mass, light scattering, and absorption) but less variability in intensive properties (e.g., mass scattering efficiency, single scattering albedo, backscatter fraction, and Ångström exponent) and the ratios of constituents. In general, ratios of chemical species were found to show greater variability than properties of the size distributions or aerosol optical properties. Even so, at higher haze concentrations with higher scattering values, various determinations of the mass scattering efficiency (MSE) at 33% relative humidity converged on values of about 3.8 ± 0.3 m^2 g^(−1), providing a firm constraint upon the description and modeling of haze optical properties. MSE values trended lower with more dilute haze but became more variable in clean air or regions of low concentrations. This cross-platform comparison resolved a number of measurement differences but also revealed that regional characterization from different platforms results in differences linked to variability in time and space. This emphasizes the need to combine such efforts with coordinated satellite and modeling studies able to characterize large-scale regional structure and variability. These comparisons also indicate that “closure” between chemical, microphysical, and optical properties across platforms to better than about 20% will require significant improvements in techniques, calibration procedures, and comparison efforts.

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Additional Information:© 2002 by the American Geophysical Union. Received 1 March 2001; Revised 16 August 2001; Accepted 30 August 2001; Published 15 October 2002. This research was funded in part by the National Science Foundation [ATM-9612891 and the NASA Global Aerosol Climatology Project NAG-5-8118 (A.D.C., S.H.); ATM-ATM-9612888 J.A.O., E.A., and A.J.] and the Aerosol Program of the NOAA Climate and Global Change Program and the NASA Global Aerosol Climatology Project (P.K.Q. and T.S.B.). We would also like to thank the following people for contributing their data to this effort: M. O. Andreae, J. Prospero, D. Baumgardner, A. Wiedensholer, A. Novak, D. Covert, L. Hughes, R. Gabriel, T. Kirchstetter, C. Neusüb, T. Novakov, A. Jayaraman, G. Shaw, and W. Cantrell. SOEST contribution 6022.
Funding AgencyGrant Number
National Oceanic and Atmospheric Administration (NOAA)UNSPECIFIED
Subject Keywords:INDOEX; data comparison; optical properties; chemistry; microphysics; size distributions
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School of Ocean and Earth Science and Technology, Georgia Tech6022
Issue or Number:D19
Record Number:CaltechAUTHORS:20141027-121819263
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Official Citation:Clarke, A. D., Howell, S., Quinn, P. K., Bates, T. S., Ogren, J. A., Andrews, E., . . . Cass, G. (2002). INDOEX aerosol: A comparison and summary of chemical, microphysical, and optical properties observed from land, ship, and aircraft. Journal of Geophysical Research: Atmospheres, 107(D19), 8033. doi: 10.1029/2001jd000572
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:50858
Deposited By: Joanne McCole
Deposited On:27 Oct 2014 20:03
Last Modified:10 Nov 2021 19:01

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