Sub-mesoscale processes play a crucial role in ocean dynamics, particularly in the energy distribution and transfer between mesoscale and sub-mesoscale systems, where many physical mechanisms remain unresolved. This study utilizes high-resolution numerical simulation data from the MITgcm, combining 0.1° mesoscale data with 0.03° sub-mesoscale data, to systematically analyze the energy changes within the eddy-mean flow system.

Based on the theoretical framework of energy equations for mean and eddy flows, we derived and calculated the mean kinetic energy (MKE), eddy kinetic energy (EKE), mean potential energy (MPE), and eddy potential energy (EPE). By comparing energy changes at different resolutions, we analyzed the impact of sub-mesoscales on the energy budget and revealed the details of energy transfer between mesoscale and sub-mesoscale eddy systems. The results show that at sub-mesoscale resolution, the energy exchange between EKE and MKE is significantly enhanced, and the energy budget mechanism at sub-mesoscales exhibits notable differences compared to mesoscale systems.

This study provides a deeper insight into the energy transfer characteristics within the sub-mesoscale eddy-mean flow system, enriching the understanding of sub-mesoscale dynamics, and offering new data and theoretical support for future research in ocean dynamics and numerical simulations.

sub-mesoscale, mesoscale, eddy, energy budget