 |
| Titel |
Dispersion of volcanic particles during Etna eruption in December 2015. Detection by ceilometer networks (Switzerland, Italy and Germany) and in situ measurements at Alpine high-altitude sites. |
| VerfasserIn |
Maxime Hervo, Nicolas Bukowiecki, Martine Collaud Coen, Gian Paolo Gobbi, Martin Gysel, Alexander Haefele, Stephan Henne, Erik Herrmann, Giovanni Martucci, Ina Mattis, Martin Steinbacher, Frank Wagner, Luca Di Liberto, Robert Holla |
| Konferenz |
EGU General Assembly 2016
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250125239
|
| Publikation (Nr.) |
 EGU/EGU2016-4794.pdf |
|
|
|
|
|
| Zusammenfassung |
| In December 2015, the Mount Etna volcano in Sicily endured the strongest eruptions in 20
years. Volcanic ashes and gases were injected up to the top of the troposphere (∼10km). The
ashes provoked the closure of the Catania airport close to the volcano, and some particles and
gases were also transported over longer distance to the North, including continental Italy,
Switzerland and Germany.
On 8th of December 2015, an aerosol layer was detected at about 4000m by a CHM15k
ceilometer above the Kleine Scheidegg in the Swiss Alps. This layer is compatible with air
masses originating at Mt. Etna during the December 4th eruptions. This layer was also
measured by the in-situ instrumentation at the Sphinx Observatory on the Jungfraujoch (3580
m a.s.l.). The observed mass of volcanic particle measured as PM10 was more than
3μg.m−3.
Many observations confirmed the volcanic origin of these particles. First, the increase in
particle mass was associated with enhanced Sulphur dioxide (SO2) levels. This enhancement
was the highest SO2 value measured in 2015. The volcanic origin was also reflected in an
increased aerosol volume in the accumulation mode size range as well as a dominant
nucleation mode (with respect to number), indicating that a significant fraction of the
SO2 was converted to particulate sulphate. Then, no black carbon increase was
detected, suggesting that the SO2 and the particle did not come from combustion.
Furthermore, the coarse mode particle size distributions suggested the presence of an ash
mode around 2-4 micrometers in optical particle diameter. The volcanic rather than
Saharan origin of the coarse mode was confirmed by the Angstrom exponent of
the single scattering albedo higher than zero. At Schneefernerhaus observatory
(close to Zugspitze), in-situ measurements were similar to the observations at the
Jungfraujoch.
Similar layers were detected by the ceilometers of the Deutscher Wetterdienst (DWD)
network in Germany (Zugspitze, Garmisch-Partenkirchen, and Hohenpeißenberg) and of the
Italian Alicenet network (http://www.alice-net.eu/). The Italians layers were especially visible
for Milan and Rome stations. For Rome, the depolarization ratio of the layer was also
measured.
The joint analysis of the available ceilometer signals allowed a clear detection and tracking of
the plume. The plausibility of ash observations were also analysed by simulating
the dispersion of the Etna volcanic plume with the Lagrangian dispersion model
FLEXPART.
These ceilometers are part of the European network E-PROFILE that will be fully
operational in 2017. This event illustrates the high potential of this ceilometer network,
especially if they are combined and harmonized. However, additional information
about the aerosol type is beneficial for the retrieval. This data could be gathered by
ground-based in-situ observations as in the present case or by advanced lidar in
general. |
|
|
|
|
|
|