A Comparison of Cyclonic Ring Structures in the Northern Sargasso Sea

Abstract

Field observations provide a data base that supports a comparison of ring structures in terms of the background Sargasso Sea environment. Five ring surveys, three from the 1967 sequence, a big baby ring and ring AL, were selected for this study. Anomalies of temperature, salinity, transport potential energy density, heat content and sound velocity have been examined using a reference which closely approximates Iselin's characteristic T-S relation for the western gyre. The results for the 1967 sequence demonstrate an initial reduction in anomaly strengths followed by strong ring stability. Comparison of two different rings, possibly equal in age, show the effect of the initial water mass conditions on anomaly strengths. Comparison of a cyclonic ring and the big baby ring reveals similar anomaly strengths and sizes in the same geographical region for rings that are assumed to be two and eleven months in age, respectively. This suggests that big baby rings can initially represent more intense perturbations to the Sargasso Sea than cyclonic ring counterparts.