Comparison of size and morphological measurements of coarse mode dust particles from Africa
Author
Reid, Jeffrey S.
Jonsson, Haflidi H.
Maring, Hal B.
Smirnov, Alexander
Savoie, Dennis L.
Cliff, Steven S.
Reid, Elizabeth A.
Livingston, John M.
Meier, Mike M.
Dubovik, Oleg
Tsay, Si-Chee
Date
2003Metadata
Show full item recordAbstract
A multitude of sensitivity studies in the literature point to the importance of proper
chemical and morphological characterization of particles when the radiative impacts of
airborne dusts are modeled. However, the community data set is based on heterogeneous
measurement methods relying on varying aerodynamic, chemical, morphological, and
optical means. During the Puerto Rico Dust Experiment, size distributions of dust particles
from Africa were measured using a variety of aerodynamic, optical, and geometric means.
Consistent with the literature, comparisons of these size distributions showed quite
dissimilar results. ‘‘Measured’’ volume median diameters varied from 2.5 to 9 mm for
various geometric, aerodynamic, optical, and optical inversion methods. Aerodynamic
systems showed mixed performance. Column integrated size distributions inverted from
AERONET Sun/sky radiance data produced somewhat reasonable results in the coarse
mode when given proper constraints and taken in the proper context. The largest
systematic errors were found in optical particle counters due to insensitivities to particle
size in the 4–10 mm region with further complications due to dust particle morphology
and index of refraction issues. As these methods can produce quite dissimilar size
distributions, considerable errors in calculated radiative properties can occur if incorrectly
modeled into dust parameters. None of the methods compared in this study can adequately
reproduce the measured mass extinction or mass scattering efficiency of the dust using
spherical geometry methods. Given all of the uncertainties in the sizing methods, we
promote the use of fundamental and quantifiable descriptors of particles such as mass as a
function of aerodynamic diameter.
Description
Journal of Geophysical Research, Vol. 108(D19), 8593
The article of record as published may be located at http://dx.doi.org/ 10.1029/2002JD002485.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.Collections
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