Rapid evolution of a Gulf Stream warm-core ring

Abstract

Gulf Stream warm-core rings form in the Slope Water between the North American continental shelf and the Gulf Stream by the separation of a north-extending meander1. The initial physical, chemical and biological properties of the core of these 100–200-km eddies are often similar to those of its parent water mass, the Sargasso Sea. A clockwise rotating remnant of the Gulf Stream circulates around the core with surface current speeds of 50–200 cm s−1. Although warm-core rings can slowly change over periods of months through interactions with the surrounding Slope Water, Gulf Stream meanders, continental slope, other rings, and the atmosphere, we have now discovered that major alterations to ring structure can occur during very short periods (2–5 days) when an interaction with the Gulf Stream is particularly intense. Such short-period interactions between a ring and the Gulf Stream are a major factor governing a ring's evolution.