We present a neural network methodology for clustering large data sets into pertinent groups. We applied this methodology to analyze the phytoplankton absorption spectra data gathered by the Laboratoire d'Océanographie de Villefranche. We first partitioned the data into 100 classes by means of a self-organizing map (SOM) and then we clustered these classes into 6 significant groups. We focused our analysis on three POMME campaigns. We were able to interpret the absorption spectra of the samples taken in the first oceanic optical layer during these campaigns, in terms of seasonal variability. We showed that spectra from the PROSOPE Mediterranean campaign, which was conducted in a different region, were strongly similar to those of the POMME-3 campaign. This analysis led us to propose regional empirical relationships, linking phytoplankton absorption spectra to pigment concentrations, that perform better than the previously derived overall relation.
© 2007 Optical Society of America
Atmospheric and ocean optics
Original Manuscript: November 10, 2006
Revised Manuscript: March 12, 2007
Manuscript Accepted: March 13, 2007
Published: May 31, 2007
Aymeric Chazottes, Michel Crépon, Annick Bricaud, Joséphine Ras, and Sylvie Thiria, "Statistical analysis of absorption spectra of phytoplankton and of pigment concentrations observed during three POMME cruises using a neural network clustering method," Appl. Opt. 46, 3790-3799 (2007)