The four illustrations below depict the formation of a warm core ring. A ring is a type of mesoscale eddy that forms when Gulf Stream meanders break off the Stream creating independent ciculatory systems. The type of ring shown below is labeled a warm core ring since warm Sargasso Sea water is trapped in the center of the ring during formation. The arrows on the diagram indicate the direction of flow.
A. Gulf Stream meander develops
B. Amplitude of the meander increases
C. Meander forms a loop and begins to pinch off
D. Ring separates from the Gulf Stream
All warm core rings share certain characteristics. All warm core rings rotate clockwise (anticyclonic). All warm core rings are found on the inshore (landward) side of the Gulf Stream. A cold core ring forms in a similar manner except they form to the south of the Gulf Stream and rotate counterclockwise (cyclonic). Rings play an important role in transferring water across the strong frontal boundary of the Gulf Stream. The formation of a warm ring results in unproductive Sargasso Sea water transferred into the productive waters of the continental margin.
As this schematic shows, warm core ring formation results in Sargasso Sea water being transported into continental shelf water. This is the only mechansim to transport surface waters across the Gulf Stream. Thus, the Gulf Stream can be accurately thought of as a barrier between the cold waters to the north and the warm waters to the south.

The next page has more information on Gulf Stream rings.
BACK NEXT