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| Titel |
Particle formation in the Arctic free troposphere during the ASTAR 2004 campaign: a case study on the influence of vertical motion on the binary homogeneous nucleation of H₂SO₄/H₂O |
| VerfasserIn |
F. Khosrawi, J. Ström, A. Minikin, R. Krejci |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 10, no. 3 ; Nr. 10, no. 3 (2010-02-02), S.1105-1120 |
| Datensatznummer |
250008032
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| Publikation (Nr.) |
 copernicus.org/acp-10-1105-2010.pdf |
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| Zusammenfassung |
| During the ASTAR (Arctic Study of Tropospheric Aerosol and Radiation)
campaign nucleation mode particles (4 to 13 nm) were quite
frequently observed at altitudes below 4000 m. However, in the
upper free troposphere, nucleation mode particles were only observed
once, namely during the flight on 24 May 2004 (7000 m). To
investigate if vertical motion were the reason for this difference that
on one particular day nucleation mode particles were observed but not
on the other days we employ a microphysical box model. The box model
simulations were performed along air parcel trajectories calculated
6-d backwards based on European Center for Medium-Range Weather
Forecasts (ECMWF) meteorological analyses using state parameters such
as pressure and temperature in combination with additional parameters
such as vertical stability. Box model simulations were performed for
the 24 May where nucleation mode particles were observed (nucleation
event) as well as for the days with measurements before and after (22
and 26 May) which are representative for no nucleation (non-nucleation
event). A nucleation burst was simulated along all
trajectories, however, in the majority of the simulations the
nucleation rate was either too low or too high so that no nucleation
mode particles were left at the time when the measurements were
performed. Further, the simulation results could be divided into three
cases. Thereby, we found that for case 1 the temperature was the only
driving mechanism for the formation of new particles while for
case 2 and 3 vertical motion have
influenced the formation of new particles. The reason why nucleation
mode particles were observed on 24 May, but not on the other days, can
be explained by the conditions under which particle formation
occurred. On 24 May the particle formation was caused by a slow
updraft, while on the other two days the particle formation was caused
by a fast updraft. |
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