Frequency of ring separations from the loop current in the Gulf of Mexico:A revised estimate

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 p revious work, the authors examine all the apparent rings since July 1973. T his new dataset includes the satellite altimetry since 1992, providing a se t of 34 consecutive ring formations. The primary advantage of altimetry is that the data remain available in the summer. One finding is that the ambig uity of whether or not a ring has separated is reduced, but not eliminated; the uncertainty with which separation "events" can he specified remains ap proximately 4 weeks, even with nearly continuous data. Primary peaks in the distribution of separation intervals are found at 6 and 11 months with a s maller peak at 4 months. If the spectrum is smoothed heavily enough, a peak in the distribution can be formed nearer 12 months, but this near-annual p eak is a result more of the smoothing than of the data.