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| Titel |
Optical, microphysical, mass and geometrical properties of aged volcanic particles observed over Athens, Greece, during the Eyjafjallajökull eruption in April 2010 through synergy of Raman lidar and sunphotometer measurements |
| VerfasserIn |
P. Kokkalis, A. Papayannis, V. Amiridis, R. E. Mamouri, I. Veselovskii, A. Kolgotin, G. Tsaknakis, N. I. Kristiansen, A. Stohl, L. Mona |
| 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 ; 13, no. 18 ; Nr. 13, no. 18 (2013-09-17), S.9303-9320 |
| Datensatznummer |
250085701
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| Publikation (Nr.) |
 copernicus.org/acp-13-9303-2013.pdf |
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| Zusammenfassung |
| Vertical profiles of the optical (extinction and backscatter coefficients,
lidar ratio and Ångström exponent), microphysical (mean effective
radius, mean refractive index, mean number concentration) and geometrical
properties as well as the mass concentration of volcanic particles from
the Eyjafjallajökull eruption were retrieved at selected heights over
Athens, Greece, using multi-wavelength Raman lidar measurements performed
during the period 21–24 April 2010. Aerosol Robotic Network (AERONET) particulate
columnar measurements along with inversion schemes were initialized together
with lidar observations to deliver the aforementioned products. The
well-known FLEXPART (FLEXible PARTicle dispersion model) model used for volcanic dispersion simulations is
initiated as well in order to estimate the horizontal and vertical
distribution of volcanic particles. Compared with the lidar measurements
within the planetary boundary layer over Athens, FLEXPART proved to be a
useful tool for determining the state of mixing of ash with other, locally
emitted aerosol types. The major findings presented in our work concern the
identification of volcanic particles layers in the form of filaments after
7-day transport from the volcanic source (approximately 4000 km away from
our site) from the surface and up to 10 km according to the lidar measurements.
Mean hourly averaged lidar signals indicated that the layer thickness of
volcanic particles ranged between 1.5 and 2.2 km. The corresponding aerosol
optical depth was found to vary from 0.01 to 0.18 at 355 nm and from 0.02 up to
0.17 at 532 nm. Furthermore, the corresponding lidar ratios (S) ranged
between 60 and 80 sr at 355 nm and 44 and 88 sr at 532 nm. The mean effective radius
of the volcanic particles estimated by applying inversion scheme to the
lidar data found to vary within the range 0.13–0.38 μm and the
refractive index ranged from 1.39+0.009i to 1.48+0.006i. This high
variability is most probably attributed to the mixing of aged volcanic
particles with other aerosol types of local origin. Finally, the LIRIC (LIdar/Radiometer Inversion Code)
lidar/sunphotometric combined inversion algorithm has been applied in order
to retrieve particle concentrations. These have been compared with FLEXPART
simulations of the vertical distribution of ash showing good agreement
concerning not only the geometrical properties of the volcanic particles
layers but also the particles mass concentration. |
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