A Trigger Mechanism for Loop Current Ring Separations

Abstract

The Loop Current in the Gulf of Mexico sheds large anticyclonic rings on an irregular basis. The authors attempt to show what actually triggers the ring separations. Pulses of increased transport through the Florida Straits, as observed by the cable data, are observed prior to each ring separation. This finding is consistent over all separation events observed in the satellite altimetry record. The pulses of transport occur approximately two to four weeks before the rings separate. The increase in transport is usually accompanied by a corresponding increase in offshore sea level, suggesting forcing from the open ocean. The delay times between the pulses of increased transport and ring separations can be shown to be significantly correlated with the length of the Loop Current. Mean sea levels over the Caribbean and Gulf also peak before the separations, on average.