Reasonable convergence has been achieved in the ocean colour community regarding the optimal method for retrieval of chlorophyll a concentration in open ocean waters (International Ocean Colour Coordinating Group (IOCCG 1998) and an algorithm round robin for such algorithms is reported by O'Reilly, Maritorena et al. (1998).
For coastal waters the situation is very much more challenging because of the greater number of degrees of freedom of the underlying scientific problem - typically spectral reflectance is considered to be a function of 3 or more independent components such as chlorophyll a concentration, coloured dissolved organic matter absorption coefficient and non-algae particle concentration (Sathyendranath, Prieur and Morel 1989).
As a consequence a wide range of algorithms have been developed within the international community for Case 2 waters and there is no clear consensus on what algorithm should be applied in what circumstances.
The Round Robin Data package will comprise CoastColour Level 1P (TOA radiances), L2 (water leaving radiance reflectances) from MERIS measurements as well as simulated and in situ reflectance data. This data package will be distributed to interested parties together with a protocol for data usage. Scientists will run their Case 2 algorithm (starting from either L1P or L2) and generating IOPs and/or concentrations. The results will be submitted back to the CoastColour team, where a comparison of these local algorithms with the CoastColour products and the standard MERIS products will be made.
The Round Robinn Data Package is available for interested parties. It was accessible via anonymous login until end of October 2011, but now we want to kindly ask you to request account data by sending us a message.
Benefit for participants
Participants to the CoastColour Round Robin will obtain insight into the CoastColour products at an early stage. They will get a detailed report on the comparison of the water products derived with their algorithm with CoastColour products.
Participants will become co-author of the final Round Robin report. It is planned to submit a synthesised version of the report for publication in a peer reviewed journal.