Minimize Transparency Products

The objective of this process is to derive several ocean colour products characterising the transparency from the spectrum of normalised water-leaving reflectances.
Within the Instrument Processing Facility (IPF), the only product is the diffuse attenuation coefficient at 490 nm, expressed in units of m-1.
The algorithm applied here is OK2-560 as described in Morel et al, 2007. It is derived as the sum of the (hypothetical) value of the diffuse attenuation coefficient for pure seawater Kw(490) and a contribution linked to the biological state of the water. The latter is expressed, in log-transform, as a polynomial of the ratio of irradiance-reflectance between 490 and 560 nm, in a very similar way to the OC4Me Chlorophyll retrieval algorithm. Since it is derived using the same bio-geophysical approach, it has the same validity domain: Case 1 waters.

Kd(490) = Kw(490) + Kbio(490) with log10(Kbio(490)) =