Kuroshio Extension and Gulf Stream dominate the Eddy Kinetic Energy intensification observed in the global ocean

Ocean mesoscale variability, including meanders and eddies, is a crucial component of the global ocean circulation. The Eddy Kinetic Energy (EKE) of these features accounts for about 90% of the ocean's total kinetic energy. This study investigates if the global ocean mesoscale variability is becoming more energetic by analyzing 30 years of satellite altimetric observations. We use two observational products: one constructed from a consistent pair of altimeters and another including all available missions. Our results reveal a significant global EKE strengthening of 1-3% per decade. The intensification is concentrated in energetic regions, particularly in the Kuroshio Extension and the Gulf Stream, which show EKE increases of ~ 50% and ~ 20%, respectively, over the last decade. These observations raise new questions about the impact of the Gulf Stream strengthening on the Atlantic meridional overturning circulation (AMOC) and challenge existing climate models, emphasizing the need for improved representation of small-scale ocean processes.