Single particle analysis of aerosols, observed in the marine boundary layer during the Monterey Area Ship Tracks Experiment (MAST), with respect to cloud droplet formation
De Bock, L.A.; Joos, P.E.; Noone, K.J.; Pockalny, R.A.; Van Grieken, R.E. (2000). Single particle analysis of aerosols, observed in the marine boundary layer during the Monterey Area Ship Tracks Experiment (MAST), with respect to cloud droplet formation. J. Atmos. Chem. 37(3): 299-329. http://dx.doi.org/10.1023/A:1006416600722
In: Journal of Atmospheric Chemistry. Reidel: Dordrecht; Boston. ISSN 0167-7764; e-ISSN 1573-0662, more
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| Keywords |
Albedo
Colloids > Aerosols
Composition > Chemical composition
Hydrometeors > Clouds
Hydrometeors > Droplets
Layers > Boundary layers > Atmospheric boundary layer
Particulates > Atmospheric particulates
Pollution effects
Indo-Pacific North East [Marine Regions]
Marine/Coastal |
| Authors | | Top |
- De Bock, L.A.
- Joos, P.E., more
- Noone, K.J.
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- Pockalny, R.A.
- Van Grieken, R.E., more
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| Abstract |
The chemical composition of individual particles >0.2 µm sampled during the MAST-experiment were analysed by SEM-EDX, in combination with multivariate techniques. The objective of this experiment was to identify the mechanisms responsible for the modification of marine stratocumulus clouds by emissions from ships and in a wider sense to provide information on the global processes involved in atmospheric modification of cloud albedo. Aerosols were examined under different MBL pollution levels (clean, intermediately polluted and moderately polluted) in five different reservoirs: background below-cloud and above-cloud aerosol; background cloud droplet residual particles; below-cloud ship plume aerosol and ship track cloud droplet residual particles. In this study a relation was provided between the aerosol emitted from the ship's stack to an effect in cloud. Additionally, a large fraction of the ambient aerosol was found to be composed of organic material or other compounds, consisting of low Z-elements, associated with chlorine. Their number fraction was largest in clean marine boundary layers, and decreased with increasing pollution levels. The fraction of 'transformed sea salt' (Na, Cl, S), on the other hand, increased with the pollution level in the MBL. Only 20% of the particles fell within the detectable range of the analysis. |
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