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| Titel |
Cloud parcel modelling of CCN activation in megacity air based on observations from Beijing and Guangzhou |
| VerfasserIn |
H. Su, P. Reutter, J. Trentmann, D. Rose, S. Gunthe, M. Simmel, A. Nowak, A. Wiedensohler, T. Zhu, U. Pöschl |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250029046
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| Zusammenfassung |
| The other team members are P. Achtert (3), M. Hu (4), M. Shao (4), and Y.H. Zhang
(4).
The activation of cloud condensation nuclei (CCN) determines the initial number of cloud
droplets, and thus influences the evolution of the cloud and formation of precipitation.
Characterizing the CCN activation process by parcel model studies with detailed cloud
microphysics and dynamics provides useful information for parameterizing the activation
process in meso-scale and global-scale models.
During the CAREBEIJING 2006 campaign in Beijing and the PRIDE-PRD2006 campaign in
Guangzhou, fast condensational growth of particles was frequently observed and the CCN
size distribution was sometimes dominated by the growing nucleation mode (Aitken
Mode) rather than by the accumulation mode. In this study we investigated the
implications of the experimental findings using a cloud parcel model with detailed
spectral cloud microphysics and with the κ-Köhler model approach for efficient and
realistic description of the effective hygroscopicity and CCN activity of aerosol
particles. The number of droplets formed at the cloud base was examined for a wide
range of updraft velocities and aerosol particle number concentrations. Moreover,
the impact of aerosol hygroscopicity, size distribution and giant CCN were also
evaluated.
References:
Reutter, P., Trentmann, J., Su, H., Simmel M., Rose, D., Wernli, H., Andreae, M.
O., and Pöschl, U.: Activation of aerosol particles as cloud condensation nuclei
(CCN) under smoky and pyro-convective conditions, manuscript in preparation,
2009
Rose, D., Gunthe, S. S., Mikhailov, E., Frank, G. P., Dusek, U., Andreae, M. O., and Pöschl,
U.: Calibration and measurement uncertainties of a continuous-flow cloud condensation
nuclei counter (DMT-CCNC): CCN activation of ammonium sulfate and sodium chloride
aerosol particles in theory and experiment, Atmos. Chem. Phys., 8, 1153-1179,
2008.
Rose, D., Nowak, A., Achtert, P., Wiedensohler, A., Hu, M., Shao, M., Zhang, Y., Andreae,
M. O., and Pöschl, U.: Cloud condensation nuclei in polluted air and biomass burning smoke
near the mega-city Guangzhou, China – Part 1: Size-resolved measurements and implications
for the modeling of aerosol particle hygroscopicity and CCN activity, Atmos. Chem. Phys.
Discuss., 8, 17343-17392, 2008.
Simmel, M. and Wurzler, S.: Condensation and activation in sectional cloud microphysical
models., Atmospheric Research 80(2-3): 218-236., 2006.
Wiedensohler, A., Cheng, Y. F., Nowak, A., Wehner, B., Achtert, P., Berghof, M., Birmili, W.,
Wu, Z. J., Hu, M., Zhu, T., Takegawa, N., Kita, K., Kondo, Y., Lou, S. R., Hofzumahaus, A.,
Holland, F., Wahner, A., Gunthe, S., Rose, D., and Pöschl, U.: Rapid Aerosol Particle Growth
and Increase of Cloud Condensation Nucleus (CCN) Activity by Secondary Aerosol
Formation: a Case Study for Regional Air Pollution in North Eastern China, J. Geophys. Res.,
submitted, 2008 |
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