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| Titel |
Retrieval of the optical depth and vertical distribution of particulate scatterers in the atmosphere using O2 A- and B-band SCIAMACHY observations over Kanpur: a case study. |
| VerfasserIn |
S. V. Sanghavi, J. V. Martonchik, J. Landgraf, U. Platt |
| 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 |
250069778
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| Zusammenfassung |
| Owing to the known distribution of O2 in the atmosphere, the strong O2 A-band has been
frequently used to derive aerosol and cloud properties from space. Using a synthetic
study, we show that the combined use of the O2 A and B-band provides additional
information on the vertical distribution of atmospheric scatterers as both bands are very
different in terms of their absorption strengths and underlying surface albedos.
SCIAMACHY onboard ENVISAT is the first instrument to provide spectral data at moderate
resolution (0.2 nm-1.5 nm) in the UV/VIS including both the O2 A- and B-bands. Using
SCIAMACHY specifications, we make combined use of these bands in an optimal
estimation algorithm. Using information content analysis and synthetic studies, we
show that our algorithm is applicable both over bright and dark surfaces for the
retrieval of the parametrized vertical profile of aerosol, in addition to the optical
thickness.
Due to computational and instrumental limitations, we restrict application to real data
to a case-study over Kanpur through the year 2003. A comparison of the results
with coincident AERONET data shows the same seasonal pattern of haziness over
Kanpur, which manifests itself in a correlation coefficient of 0.92 for non-monsoon
monthly mean AOTs. The retrieved particulate optical thicknesses are found to be
anti-correlated with the relative contrast of the apparent lambertian equivalent albedos
at 682 nm and 755 nm by a factor of 0.788, confirming the hypothesis made in
Sanghavi et al, 2010. Retrospective comparison of retrieved vertical profiles with
CALIPSO data shows that the retrieved heights are within in the seasonally expected
ranges. |
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