Figure 2.

Interannual variability of the Warm Core Ring and Cold Core Ring formation between 1980 and 2019. The regime shift (denoted by the split in the red solid line) for the Warm Core Rings is significant at the turn of the century. Note the phase change from “More Cold Core Rings—Fewer Warm Core Rings” to “More Warm Core Rings—Fewer Cold Core Rings” after the year 2000. The average formation rates for different time-periods are indicated within the figure.