There are 4 products for each
scene (this may eventually be 7 products for some scenes):
RGB - a true color
image using level 1 (i.e. at-satellite) radiance values
at 665nm, 560 nm and 443 nm.
FLH - the fluorescence line height
indicating level 1 radiance at 681 nm relative to a baseline
derived by linear interpolation between level 1 radiance values at
665nm and 709nm.
MCI - the maximum chlorophyll
index indicating level 1 radiance at 709 nm relative
to a baseline derived by linear interpolation between
level 1 radiance values at 681 nm and 735 nm.
Algal1 - the case 1 chlorophyll
product derived from level 2 (i.e. corrected to sea surface
by computing atmospheric effects) reflectance values.
The FLH and MCI products are masked to black using a suitable radiance
threshold from band 13 radiance values. The images are not rectified. The
spatial resolution is 1200m for the reduced resolution products and 300m for the
full resolution products. FLH images are sometimes affected by a sudden colour
change at one of the boundaries between the 5 cameras of MERIS.
In some cases a correction has been applied. The letters "cbCorr"
are then included in the file name.
The enhancement is not the same between dates. For FLH, MCI and Algal 1, blue
represents low chlorophyll concentrations and red/white represents high
chlorophyll concentrations ( palette shown above). FLH and MCI both have a
linear enhancement. Algal 1 has a logarithmic enhancement. The FLH enhancement
is generally comparable to extracted chlorophyll concentrations of 1 to above 10
mg/m3. The Algal 1 enhancement is generally from 0.3 to 50 mg/m3
(2002-May 2006) or 0.1 to 30 mg/m3 (May 2006 to present).