 |
| Titel |
Technical Note: Optical properties of desert aerosol with non-spherical mineral particles: data incorporated to OPAC |
| VerfasserIn |
P. Koepke, J. Gasteiger, M. Hess |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 10 ; Nr. 15, no. 10 (2015-05-29), S.5947-5956 |
| Datensatznummer |
250119765
|
| Publikation (Nr.) |
 copernicus.org/acp-15-5947-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| Mineral particles, in general, are not spheres and so the assumption
of spherical particles, instead of more realistic
shapes, has significant effects on modeled optical
properties and therefore on remote-sensing
procedures for desert aerosol and the derived radiative forcing. Thus, in a
new version of the database OPAC (Optical Properties of Aerosols and Clouds;
Hess et al., 1998), the optical properties of the mineral particles are
modeled describing the particles as spheroids with size dependent aspect
ratio distributions, but with the size distributions and the spectral
refractive indices not changed against the previous version of OPAC. The
spheroid assumption is known to substantially improve the scattering
functions but pays regard to the limited knowledge on particle shapes in an
actual case. The relative deviations of the optical properties of
non-spherical mineral particles from those of spherical particles are for the
phase function in the solar spectral range up to +60% at scattering
angles of about 130° and up to −60% in the backscatter region,
but less than 2% for the asymmetry parameter. The deviations are
generally small in the thermal infrared and for optical properties that are
independent of the scattering angle. The improved version of OPAC (4.0) is
freely available at www.rascin.net. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|