Seasonal Variability of Three-Dimensional Eddies in the Arctic Region

This study employs a high-resolution (1/24°) Massachusetts Institute of Technology General Circulation Model (MITgcm) configuration, coupled with a sea ice module, to simulate ocean parameters—including temperature, salinity, and current fields—in the Arctic Ocean. The seasonal characteristics of Arctic three-dimensional eddies are analyzed using the simulation results combined with a three-dimensional eddy identification method. The model demonstrates high accuracy in temperature, salinity, and current fields, validated against Argo data (correlation (Cor)>0.91 and root mean square errors (RMSE)<0.84) and the Copernicus Marine Environment Monitoring Service (CMEMS) current data (Cor>0.87 and RMSE<0.04). Compared to CMEMS, the MITgcm identifies approximately 1.5 times more eddies overall and over twice as many small-scale, short-lived eddies with radii under 25 km, because its higher resolution enables the detection of smaller eddies. Seasonal analysis shows that cyclonic eddies (CEs) are dominant, but their numbers approach those of anticyclonic eddies (AEs) in autumn due to wind forcing enhanced by sea ice minimization and transitional ocean stratification. Eddy kinetic energy (EKE) peaks at 300–600 m depths, with 86.2% of eddies exhibiting center deflection angles <3° in this depth range, promoting stable vertical eddy structures. As the depth increases, the combined effects of barotropic and baroclinic instabilities enhance the coherence of eddy radius and significantly strengthen the structural stabilities of three-dimensional eddies in the mid-to-deep layers. These findings enhance our understanding of the physical mechanisms governing three-dimensional eddy generation and highlight their crucial role in regulating Arctic Ocean circulation and climate feedbacks, providing a useful modeling reference for improving predictions of polar ocean dynamics.