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| Titel |
Volcanic ash over Scandinavia originating from the Grímsvötn eruptions in May 2011 |
| VerfasserIn |
M. Tesche, P. Glantz, C. Johansson, M. Norman, A. Hiebsch, A. Ansmann, D. Althausen, R. Engelmann, P. Seifert |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250063288
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| Zusammenfassung |
| In May 2011, eruptions of Iceland’s Grímsvötn volcano released huge amounts of material
into the troposphere and lower stratosphere. Volcanic ash transported to southern Scandinavia
could be identified in satellite observations and at air quality monitoring stations in Norway,
Sweden, and Finland with PM10 exceeding 100Â μg/m3 for several hours. The overpass of
the ash plume over Stockholm was also detected with a Raman lidar and a sun
photometer (SPM). The first traces of ash were identified at 1900 UTC on 24 May
2011 by an increase in PM10 concentrations and strong lidar signals within the
planetary boundary layer (PBL). A maximum ash concentration of 160Â μg/m3
was observed at 0000 UTC on 25 May 2011. A second maximum of 110Â μg/m3
occurred 4 h later. Measurements of particle size distributions at the surface showed
5 times higher concentrations of particles with diameters between 1 and 7Â μm
compared to measurements performed 24 h earlier and later, respectively. In addition, an
elevated ash layer was detected by lidar between 1.5 and 3.0 km height from 0200
to 0800Â UTC on 25 May 2011. The maximum aerosol optical thickness (AOT)
of this layer was found to be 0.3 at 532 nm while the total AOT of both the PBL
and the elevated layer was 0.6. The AOT obtained with lidar is in good agreement
with SPM measurements after sunrise. Ash mass concentrations estimated from
the lidar measurements were in the range of 140–270Â μg/m3 at 2.8 km height. |
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