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| Titel |
Simulation of SEVIRI infrared channels: a case study from the Eyjafjallajökull April/May 2010 eruption |
| VerfasserIn |
A. Kylling, R. Buras, S. Eckhardt, C. Emde, B. Mayer, A. Stohl |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 6, no. 3 ; Nr. 6, no. 3 (2013-03-13), S.649-660 |
| Datensatznummer |
250017838
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| Publikation (Nr.) |
 copernicus.org/amt-6-649-2013.pdf |
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| Zusammenfassung |
| Infrared satellite images are widely and successfully used to detect and
follow atmospheric ash from erupting volcanoes. We describe a new radiative
transfer model framework for the simulation of infrared radiances, which can
be compared directly with satellite images. This can be helpful to get
insight into the processes that affect the satellite retrievals. As input to
the radiative transfer model, the distribution of ash is provided by
simulations with the FLEXPART Lagrangian particle dispersion model,
meteorological cloud information is adopted from the ECMWF analysis and the
radiative transfer modelling is performed with the MYSTIC 3-D radiative
transfer model. The model framework is used to study an episode during the
Eyjafjallajökull eruption in 2010. It is found that to detect ash by the
reverse absorption retrieval technique, accurate representation of the ash
particle size distribution is required. Detailed investigation of individual
pixels displays the radiative effects of various combinations of ash, liquid
water and ice clouds. In order to be clearly detectable, the ash clouds need
to be located at some distance above other clouds. If ash clouds are mixed
with water clouds or are located only slightly above water clouds, detection
of the ash becomes difficult. Simulations were also made using the so-called
independent pixel approximation (IPA) instead of the fully 3-D radiative
transfer modelling. In the two simulations, different clouds (or different
parts of the clouds) or the ground are effectively emitting radiation towards
the instrument, thus causing differences in the brightness temperature of up
to ± 25 K. The presented model framework is useful for further studies
of the processes that affect satellite imagery and may be used to test both
new and existing ash retrieval algorithms. |
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