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| Titel |
New particle formation infrequently observed in Himalayan foothills – why? |
| VerfasserIn |
K. Neitola, E. Asmi, M. Komppula, A.-P. Hyvärinen, T. Raatikainen, T. S. Panwar, V. P. Sharma, H. Lihavainen |
| 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 ; 11, no. 16 ; Nr. 11, no. 16 (2011-08-19), S.8447-8458 |
| Datensatznummer |
250010014
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| Publikation (Nr.) |
 copernicus.org/acp-11-8447-2011.pdf |
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| Zusammenfassung |
| A fraction of the Himalayan aerosols originate from secondary sources, which
are currently poorly quantified. To clarify the climatic importance of
regional secondary particle formation in the Himalayas, data from 2005 to
2010 of continuous aerosol measurements at a high-altitude (2180 m) Indian
Himalayan site, Mukteshwar, were analyzed. For this period, the days were
classified, and the particle formation and growth rates were calculated for
clear new particle formation (NPF) event days. The NPF events showed a
pronounced seasonal cycle. The frequency of the events peaked in spring, when
the ratio between event and non-event days was 53 %, whereas the events
were truly sporadic on any other seasons. The annual mean particle formation
and growth rates were 0.40 cm−3 s−1 and 2.43 nm h−1,
respectively. The clear annual cycle was found to be mainly controlled by the
seasonal evolution of the Planetary Boundary Layer (PBL) height together with
local meteorological conditions. Spring NPF events were connected with
increased PBL height, and therefore characterised as boundary layer events,
while the rare events in other seasons represented lower free tropospheric
particle formation. This provides insight on the vertical extent of NPF in
the atmosphere. |
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