Publication Date:
2013-10-16
Description:
[1] Soot particles are a major absorber of shortwave radiation in the atmosphere. The mass absorption cross section is an essential quantity to describe this light absorption process. This work presents new experimental data on the mass absorption cross section of soot particles in the troposphere over Central Europe. Mass absorption cross sections were derived as the ratio between the light absorption coefficient determined by multi angle absorption photometry (MAAP), and the soot mass concentration determined by Raman spectroscopy. The Raman method is sensitive to graphitic structures present in the particle samples, and was calibrated in the laboratory using Printex ® 90 model particles. M ass absorption cross sections were determined for a number of seven observation sites, ranging between 3.9 and 7.4 m 2 g − 1 depending on measurement site and observational period. The highest values were found in a continentally aged air mass in winter, where soot particles were assumed to be mainly internally mixed . Our values are in the lower range of previously reported values, possibly due to instrumental differences to the former photometer and mass measurements. Overall, a value of 5.3 m 2 g − 1 from orthogonal regression over all samples is considered to be representative for the soot mass absorption cross section in the troposphere over Central Europe.
Print ISSN:
0148-0227
Topics:
Geosciences
,
Physics
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