 |
| Titel |
Time span and spatial scale of regional new particle formation events over Finland and Southern Sweden |
| VerfasserIn |
T. Hussein, H. Junninen, P. Tunved, A. Kristensson, M. Maso, I. Riipinen, P. P. Aalto, H.-C. Hansson, E. Swietlicki, M. Kulmala  |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 9, no. 14 ; Nr. 9, no. 14 (2009-07-17), S.4699-4716 |
| Datensatznummer |
250007510
|
| Publikation (Nr.) |
 copernicus.org/acp-9-4699-2009.pdf |
|
|
|
|
|
| Zusammenfassung |
| We investigated the time span and spatial scale of regional new particle
formation (NPF) events in Finland and Southern Sweden using measured
particle number size distributions at five background stations. We define
the time span of a NPF event as the time period from the first moment when
the newly formed mode of aerosol particles is observable below 25 nm until
the newly formed mode is not any more distinguishable from other background
modes of aerosol particles after growing to bigger sizes. We identify the
spatial scale of regional NPF events based on two independent approaches.
The first approach is based on the observation within a network of
stationary measurement stations and the second approach is based on the time
span and the history of air masses back-trajectories. According to the
second approach, about 60% and 28% of the events can be traced to
distances longer than 220 km upwind from where the events were observed in
Southern Finland (Hyytiälä) and Northern Finland (Värriö),
respectively. The analysis also showed that the observed regional NPF events
started over the continents but not over the Atlantic Ocean. The first
approach showed that although large spatial scale NPF events are frequently
observed at several locations simultaneously, they are rarely identical
(similar characteristics and temporal variations) due to differences in the
initial meteorological and geographical conditions between the stations. The
growth of the newly formed particles during large spatial scale events can
be followed for more than 30 h where the newly formed aerosol particles
end up in the Aitken mode (diameter 25–100 nm) and accumulation mode size
ranges (diameter 0.1–1 μm). This study showed clear evidence that
regional NPF events can pose a significant source for accumulation mode
particles over the Scandinavian continent provided that these findings can
be generalized to many of the air masses traveling over the European
continent. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|