Climatological aspects of the optical properties of fine/coarse mode aerosol mixtures

Authors

Thomas F. Eck, Universities Space Research AssociationFollow
B. N. Holben, NASA
Aliaksandyr Sinyuk, NASAFollow
R. T. Pinker, University of Maryland - College ParkFollow
P. Goloub, Université de Lille, France
H. Chen, Chinese Academy of SciencesFollow
B. Chatenet, Universités Paris‐Est, France
Z. Li, University of Maryland - College Park
Ramesh P. Singh, Chapman UniversityFollow
Sachchida N. Tripathi, Indian Institute of Technology - KanpurFollow
J. S. Reid, Naval Research Laboratory, Monterey, California
D. M. Giles, NASA
O. Dubovik, Université de Lille, France
N. T. O'Neill, Université de Sherbrooke, Canada
A. Smirnov, NASA
P. Wang, Chinese Academy of Sciences
X. Xia, Chinese Academy of Sciences

Document Type

Article

Publication Date

2010

Abstract

Aerosol mixtures composed of coarse mode desert dust combined with fine mode combustion generated aerosols (from fossil fuel and biomass burning sources) were investigated at three locations that are in and/or downwind of major global aerosol emission source regions. Multiyear monitoring data at Aerosol Robotic Network sites in Beijing (central eastern China), Kanpur (Indo-Gangetic Plain, northern India), and Ilorin (Nigeria, Sudanian zone of West Africa) were utilized to study the climatological characteristics of aerosol optical properties. Multiyear climatological averages of spectral single scattering albedo (SSA) versus fine mode fraction (FMF) of aerosol optical depth at 675 nm at all three sites exhibited relatively linear trends up to similar to 50% FMF. This suggests the possibility that external linear mixing of both fine and coarse mode components (weighted by FMF) dominates the SSA variation, where the SSA of each component remains relatively constant for this range of FMF only. However, it is likely that a combination of other factors is also involved in determining the dynamics of SSA as a function of FMF, such as fine mode particles adhering to coarse mode dust. The spectral variation of the climatological averaged aerosol absorption optical depth (AAOD) was nearly linear in logarithmic coordinates over the wavelength range of 440-870 nm for both the Kanpur and Ilorin sites. However, at two sites in China (Beijing and Xianghe), a distinct nonlinearity in spectral AAOD in logarithmic space was observed, suggesting the possibility of anomalously strong absorption in coarse mode aerosols increasing the 870 nm AAOD.

Comments

This article was originally published in Journal of Geophysical Research , volume 115, in 2010. DOI: 10.1029/2010JD014002

Recommended Citation

Eck, T. F., et al. (2010), Climatological aspects of the optical properties of fine/coarse mode aerosol mixtures, J. Geophys. Res., 115, D19205, doi:10.1029/2010JD014002.

Peer Reviewed

1

Copyright

American Geophysical Union