Eddy Deformation and Kinetic Energy Conversion During the Eddy‐Kuroshio Interaction East of Taiwan

Abstract

AbstractEddy‐mean flow interactions have always been of interest to researchers because they are among the causes of energy cascades. Different from most previous studies, this research concentrates on the Kuroshio Current's effect on an eddy during multiple independent elliptical eddy‐Kuroshio interactions. Eddy deformation during the eddy‐Kuroshio interaction is applied as the statistical criterion to select the typical eddies that interact with the Kuroshio east of Taiwan. There are 9 anticyclonic eddies (AEs) and 15 cyclonic eddies (CEs) that satisfy the criteria from the 1993 to 2018 satellite altimeter data. The blocking effect caused by the anti‐phase velocity at the contact interface of the CE and Kuroshio results in the eddy kinetic energy (EKE) at the CE edge being obviously inhomogeneous, while the AE does not result in the same effect. Moreover, the temporal variation in EKE during the eddy‐Kuroshio interaction precedes the AE/CE deformation by approximately 0.55/0.27 interaction cycles. The Kuroshio has different modulation mechanisms for different eddy polarities. Barotropic and baroclinic instabilities contribute to the generation of EKE, with barotropic instabilities providing more than 10 times as much as baroclinic instabilities for the AE and 4 times as much for the CE. The advection effect of the AE on the Kuroshio is in anti‐phase with the effect of the Kuroshio on the AE, which eventually makes the AE shrink. They are in phase for the CE and lead the CE to eventually become meandering.