Relating aerosol absorption due to soot, organic carbon, and dust to emission sources determined from in-situ chemical measurements 1Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA
17 Sep 2013
2Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
3Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington, USA
*now at: Departamento de Física Aplicada, Universidad de Granada, Granada, Spain
Received: 15 December 2012 – Published in Atmos. Chem. Phys. Discuss.: 06 February 2013 Abstract. Estimating the aerosol contribution to the global or regional radiative
forcing can take advantage of the relationship between the spectral aerosol
optical properties and the size and chemical composition of aerosol. Long
term global optical measurements from observational networks or satellites
can be used in such studies. Using in-situ chemical mixing state
measurements can help us to constrain the limitations of such estimates.
Revised: 24 July 2013 – Accepted: 09 August 2013 – Published: 17 September 2013
In this study, the Absorption Ångström Exponent (AAE) and the
Scattering Ångström Exponent (SAE) derived from 10 operational
AERONET sites in California are combined for deducing chemical speciation
based on wavelength dependence of the optical properties. In addition,
in-situ optical properties and single particle chemical composition measured
during three aircraft field campaigns in California between 2010 and 2011
are combined in order to validate the methodology used for the estimates of
aerosol chemistry using spectral optical properties.
Results from this study indicate a dominance of mixed types in the
classification leading to an underestimation of the primary sources, however
secondary sources are better classified. The distinction between
carbonaceous aerosols from fossil fuel and biomass burning origins is not
clear, since their optical properties are similar. On the other hand,
knowledge of the aerosol sources in California from chemical studies help to
identify other misclassification such as the dust contribution.
Citation: Cazorla, A., Bahadur, R., Suski, K. J., Cahill, J. F., Chand, D., Schmid, B., Ramanathan, V., and Prather, K. A.: Relating aerosol absorption due to soot, organic carbon, and dust to emission sources determined from in-situ chemical measurements, Atmos. Chem. Phys., 13, 9337-9350, doi:10.5194/acp-13-9337-2013, 2013.