Frequency of Ring Separations from the Loop Current in the Gulf of Mexico: A Revised Estimate

Abstract

The most energetic events in the circulation of the Gulf of Mexico are the separation of large anticyclonic rings from the Loop Current. Building on previous work, the authors examine all the apparent rings since July 1973. This new dataset includes the satellite altimetry since 1992, providing a set of 34 consecutive ring formations. The primary advantage of altimetry is that the data remain available in the summer. One finding is that the ambiguity of whether or not a ring has separated is reduced, but not eliminated; the uncertainty with which separation “events” can be specified remains approximately 4 weeks, even with nearly continuous data. Primary peaks in the distribution of separation intervals are found at 6 and 11 months with a smaller peak at 9 months. If the spectrum is smoothed heavily enough, a peak in the distribution can be formed nearer 12 months, but this near-annual peak is a result more of the smoothing than of the data.