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| Titel |
The formation and growth of ultrafine particles in two contrasting environments: a case study |
| VerfasserIn |
Sobhan Kumar Kompalli, S. Suresh Babu, K. Krishna Moorthy, Mukunda M. Gogoi, Vijayakumar S. Nair, Jai Prakash Chaubey |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 32, no. 7 ; Nr. 32, no. 7 (2014-07-22), S.817-830 |
| Datensatznummer |
250121083
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| Publikation (Nr.) |
 copernicus.org/angeo-32-817-2014.pdf |
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| Zusammenfassung |
| Formation of ultrafine particles and their subsequent growth have been
examined during new particle formation (NPF) events in two contrasting
environments under varying ambient conditions, one for a tropical semi-urban
coastal station, Trivandrum, and the other for a high-altitude
free-tropospheric Himalayan location, Hanle. At Trivandrum, NPF bursts took
place in the late evening/night hours, whereas at Hanle the burst was a
daytime event. During the nucleation period, the total number concentration
reached levels as high as ~ 15 900 cm−3 at Trivandrum, whereas
at Hanle, the total number concentration was ~ 2700 cm−3,
indicating the abundant availability of precursors at Trivandrum and the
pristine nature of Hanle. A sharp decrease was associated with NPF for the
geometric mean diameter of the size distribution, and a large increase in the
concentration of the particles in the nucleation regime
(Dp < 25 nm). Once formed, these (secondary)
aerosols grew from nucleation (diameter Dp < 25 nm)
to Aitken (25 ≤ Dp ≤ 100 nm) regime and beyond, to
the accumulation size regimes (100 ≤ Dp ≤
1000 nm), with varying growth rates (GR) for the different size regimes
at both the locations. A more rapid growth ~ 50 nm h−1 was
observed at Trivandrum, in contrast to Hanle where the growth rate ranged
from 0.1 to 20 nm h−1 for the transformation from the nucleation to
accumulation – a size regime that can potentially act as cloud condensation
nuclei (CCN). The faster coagulation led to lifetimes of < 1 h
for nucleation mode particles. |
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