Some advances and retreats in the study of ocean circulation since 1935

Abstract

This is an account of a few of the major findings about large-scale ocean circulation of the last few decades and perhaps some evaluations and comments on the past work. We have collected vast amounts of data, from conventional hydrographic measurements with bottles and thermometers, bathythermographs, CTDs, ADCPs, current meters, drogues, drifters, and satellites. And we have computers that let us process, map, and calculate at speeds that we could not have dreamed of in 1950. The data set has revealed many features new to the field, confirmed many others, corrected some serious errors of the past, and allowed many investigations that had not been possible before. Most of our findings about ocean circulation have resulted from measurements of the ocean. The major theoretical results so far-Ekman transport, western intensification, and Sverdrup transport-followed from the results of measurements. We have learned more about the manner of formation of thewaters in the various basins, and their flow from basin to basin, the circulation of the large gyres, the flow along the boundaries, the penetration of the waters from the circumpolar flow into the various oceans, the equatorial circulation, and the transports of the major currents. We have learned much of this from examining the patterns of the various tracers and from the density fields, which reflect the geostrophic flow. We have also found that some of our early views of the circulation were wrong, and it is interesting to ponder why they were wrong and whether the earlier data could have given better answers. © 2006 Springer Science+Business Media, Inc., All rights reserved.