 |
| Titel |
Investigation of nucleation events vertical extent: a long term study at two different altitude sites |
| VerfasserIn |
J. Boulon, K. Sellegri, M. Hervo, D. Picard, J.-M. Pichon, P. Fréville, P. Laj |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 12 ; Nr. 11, no. 12 (2011-06-20), S.5625-5639 |
| Datensatznummer |
250009849
|
| Publikation (Nr.) |
 copernicus.org/acp-11-5625-2011.pdf |
|
|
|
|
|
| Zusammenfassung |
| In this work we present an analysis of the occurrence of nucleation events
during more than three years of measurements at two different rural altitude
sites, the puy de Dôme research station (1465 m a.s.l.) and the Opme
station (660 m a.s.l.), central France. The collected database is a unique
combination of scanning mobility particle sizer (10–400 nm), air ion
spectrometers (from 0.8 to 42 nm for NTP-conditions), and, neutral clusters
and air ion spectrometers (from 0.8 to 42 nm for NTP-conditions)
measurements at these two different altitudes nearly located research
stations, from February 2007 to June 2010. The seasonality of the frequency
of nucleation events was studied at the puy de Dôme station and maximum of
events frequency was found during early spring and early autumn. During the
measurement period, neither the particle formation rates (J2= 1.382
± 0.195 s−1) nor the growth rates (GR1.3−20 nm = 6.20 ± 0.12 nm h−1) differ from one site to the
other on average. Hovewer, we found that, on 437 sampling days in common to
the two sites, the nucleation frequency was higher at the puy de Dôme
station (35.9 %, 157 days) than at the low elevation station of Opme
(20.8 %, 91 days). LIDAR measurements and the evolution of the potential
equivalent temperature revealed that the nucleation could be triggered either
(i) within the whole low tropospheric column at the same time from the
planetary boundary layer to the top of the interface layer (29.2 %,
47 events), (ii) above the planetary boundary layer upper limit (43.5 %,
70 events), and (iii) at low altitude and then transported, conserving
dynamic and properties, at high altitude (24.8 %, 40 events). This is the
first time that the vertical extent of nucleation can be studied over a long
observational period, allowing for a rigorous statistical analysis of the
occurrence of nucleation over the whole lower troposphere. This work
highlights the fact that nucleation can occur over a large vertical extent,
at least the whole low tropospheric column, and also the fact that it occurs
twice as frequently as actually detected in the planetary boundary layer. The
role of sulfuric acid and ions in the nucleation process was investigated at
the altitude station and no correlation was found between nucleation events
and the estimated sulfuric acid concentrations. However, the contribution of
ion-induced nucleation was found to be relatively high (12.49 ± 2.03 %
of the total nucleation rate). |
| |
|
| Teil von |
|
|
|
|
|
|
|
|