A consistent inventory of water mass factors in the intermediate and deep Pacific Ocean derived from conservative tracers

Citation:
Hamann, IM, Swift JH.  1991.  A consistent inventory of water mass factors in the intermediate and deep Pacific Ocean derived from conservative tracers. Deep-Sea Research Part a-Oceanographic Research Papers. 38:S129-S169.

Keywords:

circulation, currents, flow patterns, north pacific, salinity, south-pacific, tropical areas

Abstract:

Estimates of the characteristics and proportional importance of water mass factors are determined by exploratory multivariate Q-mode factor analysis (QMFA) of Pacific Ocean hydrographic data from the region north of 30-degrees-S. The inter-tracer ratios between potential temperature, salinity, the calculated parameters "NO" and "PO" and silicate are used to establish a matrix of similarity coefficients between all station locations. Its rotated eigenvectors ("factors") are viewed as distinct water types of the system. On individual key density surfaces QMFA shows that the spatial distribution of relative contributions from the primary factors can be linked to known or suspected water types and their subsequent spreading. The minor factors reflect smaller perturbations of the dominating ratios. Another QMFA was done in three dimensions by combining all density layers to determine factors derived from diapycnal as well as isopycnal property gradients. Two primary factors represent the opposing vertical temperature and salinity-nutrients gradient: "a deep water melange", which concentrates in the Northeast Pacific (maximum where sigma-1 greater-than-or-equal-to 31.93), and a "subtropical thermocline" factor (maximum on sigma-theta = 25.80) centered in the subtropical gyres. The spatially uneven decrease of relative contribution from a "shallow" factor as one moves down from the upper to the lower thermocline suggests areas where the exchange with the "deeper" factor may be enhanced.

Notes:

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DOI:

10.1016/S0198-0149(12)80008-2