Role of Air-Sea Interaction in the Energy Balance of Anticyclonic and Cyclonic Eddies in the Kuroshio Extension

Using eddy-resolving Community Earth System Model (CESM) simulations, this study investigates mesoscale eddy energetics and the role of air-sea interaction for both anticyclonic and cyclonic eddies (AEs and CEs) in the Kuroshio Extension (KE) region. Based on energy budget analysis and eddy tracking algorithm, it is found that eddy energy balance depicts similar characteristics for AEs and CEs. The eddy kinetic energy (EKE) is generated through barotropic instability, vertical buoyancy flux, as well as transported from the upper stream Kuroshio. In addition, the temperature variance, which is directly related to eddy potential energy, is maintained by baroclinic instability. Air-sea heat flux and wind stress act as eddy killers to move energy from oceanic eddies. For both AEs and CEs, heat exchange between atmosphere and oceanic eddies dominates the dissipation of temperature variance and accounts for more than 60% and 72% of the total dissipation, respectively. In comparison, the role of wind power in damping the EKE is relatively small. Only 14% (5%) of EKE dissipation in AEs (CEs) is attributed to eddy wind power. The Kuroshio Extension (KE) is one of the most eddy-rich regions in the global ocean, where mesoscale air-sea interaction exerts substantial impacts on the mid-latitude climate and multi-scale oceanic processes. Previous studies have proven that mesoscale air-sea interaction draws energy from mesoscale eddies and damps the eddy activity, but whether this damping effect relies on the polarity of eddy remains unknown. Based on an eddy-resolving climate model simulation, this study calculates the eddy energy budget for both anticyclonic and cyclonic eddies (AEs and CEs) in the KE region. Using energy budget analysis and eddy tracking method, we find that the energy balance of AEs and CEs depicts similar characteristics. For both AEs and CEs, air-sea heat exchange dominates the eddy potential energy dissipation, while the role of eddy wind power in damping the eddy kinetic energy is relatively small. This study will be a step toward understanding eddy dynamics in strong oceanic current regions in the global ocean. Air-sea interaction plays a dissipating role for anticyclonic and cyclonic eddies Air-sea heat exchange dominates the dissipation of eddy-induced temperature variance with contribution of more than 60% Wind power dissipates EKE for both anticyclonic and cyclonic eddies, accounting for 14% and 5% of EKE dissipation