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| Titel |
Microwave scattering from ice crystals: how much parameters can differ from equal volume spheres |
| VerfasserIn |
F. Teschl, W. L. Randeu, R. Teschl |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7340
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| Digitales Dokument |
URL |
| Erschienen |
In: Precipitation: Measurement, Climatology, Remote Sensing, and Modeling (EGU Session 2009) ; Nr. 25 (2010-06-08), S.127-133 |
| Datensatznummer |
250015747
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| Publikation (Nr.) |
 copernicus.org/adgeo-25-127-2010.pdf |
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| Zusammenfassung |
The scattering properties of ice crystals at centimeter
and millimeter wavelengths are fundamental for their measurement with radars
or radiometers as well as for many other applications in remote sensing.
Only the scattering properties of homogeneous spheres can be
computed in a mathematically exact way using the Mie theory. Therefore, for
many approaches ice crystals and other frozen hydrometeors are approximated
by ice spheres that have the same volume as the crystal or hydrometeor – so
called equal volume spheres. However, many frozen hydrometeors are
non-spherical. They exist in a huge variety of shapes and exhibit different
mixtures of ice, water and air. Therefore it is desirable to accurately
compute scattering from non-spherical particles in order to clearly
understand the effect the shape of a hydrometeor has on its scattering
pattern.
In this study, single scattering parameters like scattering cross section
(Csca) and absorption cross section (Cabs) were calculated for six pristine
ice crystals by means of the Discrete Dipole Approximation (DDA). The
calculations were carried out for frequencies from 1 GHz to 300 GHz –
leading to size parameters of up to 4.
The study calculates the scattering parameters for randomly oriented ice
crystals and investigates to what extent the exact scattering parameters can
differ from an approximation by equal volume spheres. |
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