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| Titel |
Long-term observations of new particle formation in Eastern Mediterranean atmosphere |
| VerfasserIn |
Nikolaos Kalivitis, Giorgos Kouvarakis, Aikaterini Bougiatioti, Iasonas Stavroulas, Hanna E. Manninen, Markku Kulmala  , Veli-Matti Kerminen, Nikolaos Mihalopoulos |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250112311
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| Publikation (Nr.) |
 EGU/EGU2015-12460.pdf |
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| Zusammenfassung |
| New particle formation (NPF) is a frequent phenomenon in the marine boundary layer (MBL)
atmosphere. So far, for the Mediterranean region, NPF events have been reported in the
literature but this is the first time that long-term continuous measurements are used to identify
and characterize NPF events.
We analyzed continuous measurements from the environmental research station of
University of Crete at Finokalia, Crete, Greece (35Ë 20´ N, 25Ë 40´ E, 250m a.s.l).
The site has been reported to be representative for the eastern Mediterranean MBL
atmosphere. Number size distributions of particles in the size range 8 to 848 nm
were measured using scanning mobility particle sizer (SMPS) since 2008 (with
additional data available for 2004 and 2005 ). Particle growth rates up to the diameter of
25 nm were calculated as well as the condensational sink Additionally, mobility
distributions of air ions were measured using an Air Ion Spectrometer (AIS) in the
mobility range between 3.2 and 0.0013 cm2V-1s-1 (0.8-42 nm ) for the periods April
2008-April 2009 and December 2012-December 2013. During the NPF event days,
the formation and growth rates of sub-3 nm ions could be calculated from AIS
data.
We found for the Eastern Mediterranean MBL, 22% of the available days could be identified
as event days. Although Finokalia is a sub-tropical site with intense photochemistry leading
to the production of high concentrations of sulfuric acid, the necessary compound for
triggering atmospheric nucleation, NPF at Finokalia has been found to be less frequent than
in other locations across Europe. However, NPF takes place all year long indicating that the
necessary precursors are available throughout the year. The probability of an event to take
place was greatly dependent on the condensational sink, which was two times lower on event
than non-event days. The growth rates of the fresh particles presented an annual
cycle with maximum values in summer and the average growth rate to 25 nm for all
the events was 4.9 ±0.7 nm h-1. Using air ion mobility distributions for the two
periods we calculated average growth rate of 2.9 nm h-1 for the diameters 1.5 -3
nm. |
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