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| Titel |
Estimating cloud optical thickness and associated surface UV irradiance from SEVIRI by implementing a semi-analytical cloud retrieval algorithm |
| VerfasserIn |
P. Pandey, K. Ridder, D. Gillotay, N. P. M. Lipzig |
| 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 ; 12, no. 17 ; Nr. 12, no. 17 (2012-09-06), S.7961-7975 |
| Datensatznummer |
250011428
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| Publikation (Nr.) |
 copernicus.org/acp-12-7961-2012.pdf |
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| Zusammenfassung |
| In this paper, we describe the implementation of the Semi-Analytical Cloud
Retrieval Algorithm (SACURA), to obtain scaled cloud optical thickness
(SCOT) from satellite imagery acquired with the SEVIRI instrument and
surface UV irradiance levels. In estimation of SCOT particular care is given
to the proper specification of the background (i.e. cloud-free) spectral
albedo and the retrieval of the cloud water phase from reflectance ratios in
SEVIRI's 0.6 μm and 1.6 μm spectral bands. The SACURA scheme
is then applied to daytime SEVIRI imagery over Europe, for the month of June
2006, at 15-min time increments. The resulting SCOT fields are compared
with values obtained by the CloudSat experimental satellite mission,
yielding a negligible bias, correlation coefficients ranging from 0.51 to
0.78, and a root mean square difference of 1 to 2 SCOT increments. These
findings compare favourably to results from similar intercomparison
exercises reported in the literature. Based on the retrieved SCOT from
SEVIRI and radiative transfer modelling approach, simple parameterisations
are proposed to estimate the surface UV-A and UV-B irradiance. The
validation of the modelled UV-A and UV-B irradiance against the measurements
over two Belgian stations, Redu and Ostend, indicate good agreement with the
high correlation, index of agreement and low bias. The SCOT fields estimated
by implementing SACURA on imagery from geostationary satellite are reliable
and its impact on surface UV irradiance levels is well produced. |
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