Temperature-salinity relationships in the surface layers of the eastern Gulf of Mexico in August, 1966

Abstract

A two-week cruise in the Eastern Gulf of Mexico using continuous profile recording salinity/temperature/depth (STD) equipment as the primary means for acquiring in situ data provides the basis for an examination of the water masses and circulation features present during August, 1966. Attention is focused on the upper 300 meters. Caribbean waters flowing in through the Yucatan Strait interact with resident Gulf of Mexico waters to create a dumb-bell shaped circulation pattern in the deeper waters of the Eastern Gulf. A large, well-developed, anticyclonic Northern Loop centered near 26° N ., 88° W. dominates the circulation. An elongated anticyclonic scaller loop extends north-northwestward from the western tip of Cuba (Cuban Loop) . The water masses in these circulation patterns are delineated into three distinct kinds based on significant characteristic temperature versus salinity relationship differences in the upper 300 meters. The Eastern Gulf Loop waters are categorized as Right-Hand (of the loop flow) and Left-Hand waters. The former is practically identical to the inflowing Yucatan Current waters. While the characteristic water mass of the western Gulf of Mexico is similar to the Left-Hand waters, there are sufficiently distinctive differences to warrant its classification as a unique intermediate water mass between the Right-Hand and Left-Hand waters. The adaptability and performance evaluation of the STD equipment in quasi-synoptic oceanographic surveying is also presented.