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Titel |
Analysis of number size distributions of tropical free tropospheric aerosol particles observed at Pico Espejo (4765 m a.s.l.), Venezuela |
VerfasserIn |
T. Schmeissner, R. Krejci, J. Ström, W. Birmili, A. Wiedensohler, G. Hochschild, J. Gross, P. Hoffmann, S. Calderon |
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. 7 ; Nr. 11, no. 7 (2011-04-07), S.3319-3332 |
Datensatznummer |
250009595
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Publikation (Nr.) |
copernicus.org/acp-11-3319-2011.pdf |
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Zusammenfassung |
The first long-term measurements of aerosol number and size distributions in
South-American tropical free troposphere (FT) were performed from March 2007
until March 2009. The measurements took place at the high altitude
Atmospheric Research Station Alexander von Humboldt. The station is located
on top of the Sierra Nevada mountain ridge at 4765 m a.s.l. nearby the city
of Mérida, Venezuela. Aerosol size distribution and number concentration
data was obtained with a custom-built Differential Mobility Particle Sizer
(DMPS) system and a Condensational Particle Counter (CPC). The analysis of
the annual and diurnal variability of the tropical FT aerosol focused mainly
on possible links to the atmospheric general circulation in the tropics.
Considerable annual and diurnal cycles of the particle number concentration
were observed. Highest total particle number concentrations were measured
during the dry season (January–March, 519 ± 613 cm−3), lowest
during the wet season (July–September, 318 ± 194 cm−3). The more
humid FT (relative humidity (RH) range 50–95 %) contained generally higher
aerosol particle number concentrations (573 ± 768 cm−3 during dry
season, 320 ± 195 cm−3 during wet season) than the dry FT
(RH < 50 %, 454 ± 332 cm−3 during dry season,
275 ± 172 cm−3 during wet season), indicating the importance of
convection for aerosol distributions in the tropical FT. The diurnal cycle in
the variability of the particle number concentration was mainly driven by
local orography. |
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