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| Titel |
Evaluation of MERIS products from Baltic Sea coastal waters rich in CDOM |
| VerfasserIn |
J. M. Beltrán-Abaunza, S. Kratzer, C. Brockmann |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1812-0784
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| Digitales Dokument |
URL |
| Erschienen |
In: Ocean Science ; 10, no. 3 ; Nr. 10, no. 3 (2014-05-23), S.377-396 |
| Datensatznummer |
250116997
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| Publikation (Nr.) |
 copernicus.org/os-10-377-2014.pdf |
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| Zusammenfassung |
| In this study, retrievals of the medium resolution imaging
spectrometer (MERIS) reflectances and water quality products using four
different coastal processing algorithms freely available are
assessed by comparison against sea-truthing data. The study is based
on a pair-wise comparison using processor-dependent quality flags
for the retrieval of valid common macro-pixels. This assessment is
required in order to ensure the reliability of monitoring systems
based on MERIS data, such as the Swedish coastal and lake monitoring
system (http://vattenkvalitet.se). The results show that the
pre-processing with the Improved Contrast between Ocean and Land
(ICOL) processor, correcting for adjacency effects, improves the
retrieval of spectral reflectance for all processors. Therefore, it
is recommended that the ICOL processor should be applied when Baltic
coastal waters are investigated. Chlorophyll was retrieved best
using the FUB (Free University of Berlin) processing algorithm,
although overestimations in the range 18–26.5%, dependent on
the compared pairs, were obtained. At low chlorophyll
concentrations (< 2.5 mg m−3), data dispersion dominated
in the retrievals with the MEGS (MERIS ground segment processor)
processor. The lowest bias and data dispersion were obtained with MEGS
for suspended particulate matter, for which overestimations in the
range of 8–16% were found. Only the FUB retrieved CDOM
(coloured dissolved organic matter) correlate with in situ
values. However, a large systematic underestimation appears in the
estimates that nevertheless may be corrected for by using a local
correction factor. The MEGS has the potential to be used as an
operational processing algorithm for the Himmerfjärden bay and
adjacent areas, but it requires further improvement of the
atmospheric correction for the blue bands and better definition at
relatively low chlorophyll concentrations in the presence of high CDOM
attenuation. |
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