Abstract: Airborne elemental carbon is a substance which has a significant effect on global circulation models. This project was designed to determine the viability of using a worldwide network of ~200 radiometers, known as the Aerosol Robotics Network (AERONET) for the collection of atmospheric elemental carbon concentrations. The information obtained will then be used to improve climate circulation models that rely on accurate estimations of this highly absorbing aerosol.

Atmospheric elemental carbon concentrations ([EC], mg/m3) for Baltimore, MD (July-November 2002) were obtained from the EPA while scattering coefficients at ambient humidity (ssp, m-1) were obtained from Dr. Philip Hopke of Clarkson University. The aerosol optical thickness (t), the Angstrom exponent, the single scattering albedo (SSA), and the column concentration of black carbon ([BC], mg/m2) were obtained from the AERONET database. By scaling the black carbon concentration using the equation listed, we hope to show that the black carbon concentrations measured by AERONET are directly proportional to the EPA elemental carbon measurements.

Analysis of the available data indicates that this relation provides a meaningful correlation between the AERONET and EPA data, with a higher correlation corresponding to more data - irrespective of whether all data values were taken within the same hour. Predicted concentrations were found to be consistently biased low when compared to EPA values. Several sources of possible bias have been identified but are not addressed in this preliminary work.