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| Titel |
A statistical analysis of North East Atlantic (submicron) aerosol size distributions |
| VerfasserIn |
M. Dall'Osto, C. Monahan, R. Greaney, D. C. S. Beddows, R. M. Harrison, D. Ceburnis, C. D. O'Dowd |
| 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. 24 ; Nr. 11, no. 24 (2011-12-15), S.12567-12578 |
| Datensatznummer |
250010265
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| Publikation (Nr.) |
 copernicus.org/acp-11-12567-2011.pdf |
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| Zusammenfassung |
| The Global Atmospheric Watch research station at Mace Head (Ireland) offers
the possibility to sample some of the cleanest air masses being imported
into Europe as well as some of the most polluted being exported out of
Europe. We present a statistical cluster analysis of the physical
characteristics of aerosol size distributions in air ranging from the
cleanest to the most polluted for the year 2008. Data coverage achieved was
75% throughout the year. By applying the Hartigan-Wong k-Means method, 12
clusters were identified as systematically occurring. These 12 clusters
could be further combined into 4 categories with similar characteristics,
namely: coastal nucleation category (occurring 21.3 % of the time), open
ocean nucleation category (occurring 32.6% of the time), background clean
marine category (occurring 26.1% of the time) and anthropogenic category
(occurring 20% of the time) aerosol size distributions. The coastal
nucleation category is characterised by a clear and dominant nucleation mode
at sizes less than 10 nm while the open ocean nucleation category is
characterised by a dominant Aitken mode between 15 nm and 50 nm. The
background clean marine aerosol exhibited a clear bimodality in the
sub-micron size distribution, with although it should be noted that either
the Aitken mode or the accumulation mode may dominate the number
concentration. However, peculiar background clean marine size distributions
with coarser accumulation modes are also observed during winter months. By
contrast, the continentally-influenced size distributions are generally more
monomodal (accumulation), albeit with traces of bimodality. The open ocean
category occurs more often during May, June and July, corresponding with the
North East (NE) Atlantic high biological period. Combined with the
relatively high percentage frequency of occurrence (32.6%), this suggests
that the marine biota is an important source of new nano aerosol particles
in NE Atlantic Air. |
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