Future evolution of an eddy rich ocean associated with enhanced east Atlantic storminess in a coupled model projection

Improved representation of air-sea fluxes afforded by eddy-rich oceans in high-resolution coupled ocean-atmosphere models may modify the tracks and intensity of storms and their response to climate change. We examine changes in winter surface ocean conditions and storminess associated with moving from an eddy-permitting (1/4°, HM) to an eddy-rich (1/12°, HH) ocean in control and climate change (SSP585) simulations of the HadGEM3-GC3.1 model in which atmosphere resolution is kept at 25 km. Differences in North Atlantic climate in the control runs stem from a revised location of the Gulf Stream in the eddy-rich model. Projections reveal greater warming in the western Atlantic in HH than HM and a pronounced increase in eastern Atlantic storminess with changes six times greater than in the eddy-permitting model. This increase is associated with the distinctive long-term evolution of the North Atlantic warming hole and the Gulf Stream separation in the eddy-rich model.