Abstract: 

Mesoscale eddies play an essential role in mediating the exchange of physical and biogeochemical tracers between the coastal and open ocean environments. Recent studies of the Eastern Boundary Upwelling Systems (EBUSs) pointed toward a suppression effect of surface warming on the intensity of mesoscale eddies. Yet much less is known about this surface warming impact on eddy-induced isopycnal mixing across EBUSs, an interior process capable of driving long-range tracer transfer. In this study, we investigate the relatively long-term impact of surface warming on isopycnal eddy mixing across EBUSs using a set of eddy-resolving, process-based simulations. The multiple-tracer-inversion approach is adopted to infer the variations of isopycnal eddy diffusivity, hence mesoscale mixing efficiency, as surface warming is strengthened. Such variations are then interpreted via established theories of eddy dynamics across continental margins. This study offers insights into the responses of mesoscale eddies in mediating coastal-ocean exchanges and the physical factors governing such responses in a warming scenario.