Ultra-chaos in a meandering jet flow

Abstract

Understanding the trajectories of passive particles, such as drifters and/or pollutants in geophysical flows, is crucial due to the mostly chaotic nature of such flows. Recently, a novel concept, namely ultra-chaos, has been introduced, which exhibits statistics instability with respect to small disturbances, in contrast to a normal-chaos that has statistics stability. However, quite a few ultra-chaotic systems have been reported to date. This study aims to analyze the trajectories of passive drifters and/or pollutants in a meandering shear flow, with particular emphasis on the prevalence of ultra-chaotic motion. It is found that the ultra-chaotic behavior of passive drifters and/or pollutants is widespread in the ocean jet flow, representing a higher disorder in comparison to the conventional normal-chaos. Obviously, an ultra-chaotic motion of passive drifters and/or pollutants might greatly enhance their dissemination. These findings might deepen our understandings about chaotic motions in geophysical flows, and further confirms the wide existence of ultra-chaos as a new concept.