20.
Ferreira M. M. C., Faria C. G., Paes E. T., “Oceanographic characterization of northern São Paulo Coast: a chemometric study”. Chemometr. Intell. Lab. Syst., 47(2), 289-297 (May 1999).
[Special issue with contributions from Conferentia Chemometrica CC'97 held in Budapest, Hungary on 21 - 23 August 1997. See Notes.]
[Article in section: Classical Chemometrics.]

Abstract.
A study of the northern Sao Paulo Brazilian coast was carried out by four survey cruises during the summers of 1985/1986 and
winters of 1986/1987. In this work, the seasonal variations of physical parameters and chemical composition of marine waters
collected during these four cruises are investigated through the multivariate approaches of principal component (PCA) and
hierarchical cluster analysis (HCA), besides the application of the traditional thermohaline analysis. The 'island effect', coastal
and shelf break upwelling phenomena and its influence in the phytoplankton community are clearly visualized through the spatial
interpolation of PCA scores and of chlorophyll concentration for the column water profiles. The intense penetration of tropical
water mass (TW) over the continental shelf towards the coast observed during the winter 1987 cruise, can also be visualized
through the scores contour plots. Complementing the usual thermohaline analysis, chemometrics has shown that other elements
such as NO₃^-, PO₄^3- and O₂ should be taken into account especially when biological processes are important.

Keywords.
Principal component analysis (PCA); Hierarchical cluster analysis (HCA); Chemometrics; Oceanography; Water masses; Upwelling.

Keywords Plus.