Oceanographic characterization of northern Sao Paulo Coast: a chemometric study

A study of the northern Sao Paulo Brazilian coast was carried out by four s urvey cruises during the summers of 1985/1986 and winters of 1986/1987. In this work, the seasonal variations of physical parameters and chemical comp osition of marine waters collected during these four cruises are investigat ed through the multivariate approaches of principal component (PCA) and hie rarchical cluster analysis (HCA), besides the application of the traditiona l thermohaline analysis. The 'island effect', coastal and shelf break upwel ling phenomena and its influence in the phytoplankton community are clearly visualized through the spatial interpolation of PCA scores and of chloroph yll concentration for the column water profiles. The intense penetration of tropical water mass (TW) over the continental shelf towards the coast obse rved during the winter 1987 cruise, can also be visualized through the scor es contour plots. Complementing the usual thermohaline analysis, chemometri cs has shown that other elements such as NO3-, PO43- and O-2 should be take n into account especially when biological processes are important. (C) 1999 Elsevier Science B.V. All rights reserved.