An analysis of AERONET aerosol absorption properties and classifications representative of aerosol source regions

D. M. Giles, B. N. Holben, T. F. Eck, A. Sinyuk, A. Smirnov, I. Slutsker, R. R. Dickerson, A. M. Thompson, J. S. Schafer

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230 Scopus citations

Abstract

Partitioning of mineral dust, pollution, smoke, and mixtures using remote sensing techniques can help improve accuracy of satellite retrievals and assessments of the aerosol radiative impact on climate. Spectral aerosol optical depth (τ) and single scattering albedo (ω0) from Aerosol Robotic Network (AERONET) measurements are used to form absorption (i.e., ω0 and absorption Ångström exponent (αabs)) and size (i.e., extinction Ångström exponent (αext) and fine mode fraction of τ) relationships to infer dominant aerosol types. Using the long-term AERONET data set (1999-2010), 19 sites are grouped by aerosol type based on known source regions to (1) determine the average ω0 and αabs at each site (expanding upon previous work), (2) perform a sensitivity study on αabs by varying the spectral ω0, and (3) test the ability of each absorption and size relationship to distinguish aerosol types. The spectral ω0 averages indicate slightly more aerosol absorption (i.e., a 0.0 < δω0 ≤ 0.02 decrease) than in previous work, and optical mixtures of pollution and smoke with dust show stronger absorption than dust alone. Frequency distributions of αabs show significant overlap among aerosol type categories, and at least 10% of the αabs retrievals in each category are below 1.0. Perturbing the spectral ω0 by ±0.03 induces significant αabs changes from the unperturbed value by at least ~±0.6 for Dust, ~±0.2 for Mixed, and ~±0.1 for Urban/Industrial and Biomass Burning. The ωo440nm and αext440-870nm relationship shows the best separation among aerosol type clusters, providing a simple technique for determining aerosol type from surface- and future space-based instrumentation.

Original languageEnglish (US)
Article numberD17203
JournalJournal of Geophysical Research Atmospheres
Volume117
Issue number17
DOIs
StatePublished - 2012

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

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