Shoreward shift of oceanic mesoscale activity over the last three decades

Oceanic mesoscale activity critically mediates the cross-shelf exchange of heat, nutrients, carbon, and pollutants. While its meridional shifts under global warming are well studied, zonal migration remains unknown. Here, based on multi-source observation and reanalysis datasets, we find that zonal centroids of both global mesoscale eddy kinetic energy (EKE) and global sea surface temperature gradient magnitudes have shifted shoreward at approximately 35.4 ± 22.5 and 34.4 ± 20.3 km per decade respectively over the last three decades (1993-2022). Energy budget analysis indicated that a shoreward shift of wind power and baroclinic energy conversion under global warming primarily has occurred in parallel with the EKE onshore migration. These shifts are reshaping coastal-open ocean exchanges, and thereby are essential for predicting coastal ecosystem resilience under climate change.