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GlobColour Products Description
Merging Methods
At the start of the GlobColour project three merging techniques
were identified as the basis for further testing (see the PUG
for further details):
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Simple averaging (AV);
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Weighted averaging (AVW) with weightings based on the
sensor/product characterisation;
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GSM model based on Maritorena and Siegel (2005, Remote
Sensing of Environment) paper.
At the end of phase two the following recommendations were made
(see the PVAR
for further details):
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Fully normalized water-leaving radiances (Lxxx): The
statistics were slightly better when using the weighted
average than the simple averaging, so the weighted averaging
was chosen.
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Chlorophyll (CHL1): GSM provided the best fit to in-situ
chlorophyll and had the added advantages of providing other
products and the ability to calculate pixel-by-pixel error
bars. The linked products, also output from the GSM model, are
Coloured dissolved and detrital organic materials (CDM) and
Particulate back-scattering coefficient (bbp).
The remaining products are then derived as follows (see the PUG
for further details):
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The diffuse attenuation coefficient at 490 nm, Kd(490), is
derived from the merged chlorophyll.
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The "excess of radiance" at 555 nm, EL555, is derived from
the merged chlorophyll and the merged fully normalized
water-leaving radiances.
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The aerosol optical thickness at 865 nm, T865, is derived by
simple averaging of the aerosol optical thickness provided by
individual sensors at the same wavelength.
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Total Suspended Matter (TSM), CDM and Case II Chlorophyll
(CHL2) are also products from just the MERIS data.
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Cloud Fraction (CF) based on classification and statistical
methods.
The European Service for Ocean Colour - GlobColour is an ESA
Data User Element Project
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