Publication Date:
2015-09-06
Description:
This work presents measurements of the spectral extinction of black carbon aerosol from 400 nm to 15 μ m. The aerosol was generated using a Mini-CAST soot generator and then allowed to circulate in an aerosol cell where its extinction was measured using a grating spectrometer in the visible, and a Fourier transform spectrometer in the infra-red. Size distribution, number concentration, and mass extinction cross-sections have also been obtained using single particle aerosol samplers. A mean mass extinction cross-section at 550 nm of 8.3 ± 1.6 m 2 g −1 is found which, assuming a reasonable single scatter albedo of 0.2, corresponds to a mass absorption cross-section of 6.6 ± 1.3 m 2 g −1 . This compares well with previously reported literature values. Computer analysis of electron microscope images of the particles provides independent confirmation of the size distribution as well as fractal parameters of the black carbon aerosol. The aerosol properties presented in this work are representative of very fresh, uncoated black carbon aerosol. After atmospheric processing of such aerosols (which could include mixing with other constituents and structural changes), different optical properties would be expected.
Print ISSN:
0148-0227
Topics:
Geosciences
,
Physics
