Dynamical Characterization of the Loop Current Attractor

The Gulf of Mexico circulation is modulated by a mesoscale current, the Loop Current (LC), and large anticyclonic eddies that detach from it. The LC dynamics are recurrent, and its evolution is in and from a few preferential states. This observation points to the existence of a low-dimensional dynamical attractor. Building upon advancements in dynamical system theory, this work characterizes the average and instantaneous dimensions of such an attractor. The instantaneous dimension and its evolution in time are compared among an altimeter-based data set, an ocean reanalysis and an operational hindcast. The LC complexity, measured by its dimension, differs among them, especially when the dimension is high. During shedding events, differences between datasets emerge in the second principal component. The information provided by this analysis is relevant to operational ocean forecasts and points to where improvement should occur.