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European
Seas Regional Data Sets
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The Global Environment
Monitoring Unit is maintaining an archive of ocean colour derived
products for the European seas, over the geographical domain 40W-55E,
10N-80N (see domain on the right). This site shows maps of chlorophyll
a concentration for specific regions covering the European Atlantic
sector from the Arctic to the Cape Verde Islands, the North Sea, Baltic
Sea, Mediterranean Sea, Black Sea and Caspian Sea.
The time series contains daily, 8-day and monthly maps derived from
SeaWiFS and MODIS for the period Sep. 1997 to present. These maps have
an approximate resolution of 2-km and are obtained after processing of
all top-of-atmosphere full resolution imagery available for the domain.
The processor used for the development of the archive is SeaDAS version
4.8.
The archive contains several categories of products:
- aerosol description (optical thickness and
Ångström
exponent),
- ocean surface apparent optical properties: normalized
water leaving
radiances Lwn,
diffuse attenuation coefficient Kd,
- concentrations of optically significant constituents:
Chlorophyll a,
total suspended matter,
- inherent optical properties: absorption,
backscattering,
- photosynthetically available radiation (PAR, for SeaWiFS
only).
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Global
Data Sets
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| The GEM also maintains a
global archive of ocean colour derived data sets, based on SeaWiFS and
MODIS. Emphasis is given for the study of the global oceans with
monthly maps of aerosol optical thickness, normalized water leaving
radiances, diffuse attenuation coefficient, chlorophyll a concentration
and PAR.
Moreover, chlorophyll a and PAR
time series are used to
compute global primary production with a depth- and wavelength-resolved
primary productivity model (see example of annual PP estimate on the
right). |
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Northern Adriatic Sea
validation time series
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As a product of reference
for calibration purposes and for comparison with the outputs of its own
algorithms, the Unit keeps an ocean colour data archive focused on the
Northern Adriatic Sea, where the Acqua Alta Oceanographic Tower
measurement site is located. This web site shows the SeaWiFS series for
this location processed with the SeaDAS software package.
Selected references for validation studies:
- Mélin, F., Zibordi, G., Berthon, J.-F.:
Assessment of SeaWiFS atmospheric and marine products for the Northern
Adriatic Sea. IEEE
Trans. Geosci. Remote Sens., 41, 548-558, 2003.
- Mélin, F., Berthon, J.-F., Zibordi, G.:
Assessment of apparent and inherent optical properties derived from
SeaWiFS with field data. Remote
Sens. Environ., 97, 540-553, 2005.
- Zibordi, G., Mélin, F., Berthon, J.-F.:
Comparison of SeaWiFS, MODIS and MERIS radiometric products at a
coastal site. Geophys.
Res. Lett., 33, L06617, 10.1029/2006GL025778,
2006.
- Zibordi, G., Mélin, F., Berthon, J.-F.: A
time series of above-water radiometric measurements for coastal water
monitoring and remote sensing product validation. IEEE Geosci. Remote
Sens. Lett., 3, 120-124, 10.1109/LGRS.2005.858486, 2006.
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Acknowledgements
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| The
Ocean Biology Processing Group of NASA is acknowledged for the
distribution of Level-1 to Level-3 SeaWiFS and MODIS products, and for
the availability of SeaDAS and the associated support. |
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