Presenter: LeAnn Conlon (LANL)

Description:
The hydrography and dynamics of the North Atlantic are critical for global circulation, yet often difficult to model accurately. These difficulties can be traced in part due to the small Rossby radius implying a smaller required resolution to resolve eddies at higher latitudes. One such impact of unresolved eddies and poor parameterizations is a deficient overturning circulation. We investigate the impacts of the strength of resolved vs. parameterized mesoscale eddies on the ocean circulation, biases, and meridional overturning circulation in the North Atlantic using the Department of Energy's Energy Exascale Earth System Model (E3SM).  We compare model output from several different global simulations with varying strengths of the Gent McWilliams parameterization in an effort to determine the effect of eddy driven mixing in the North Atlantic and to improve sea ice biases and a weak AMOC. Consistent with previous studies, we found that mesoscale eddies have a leading impact on the circulation in the North Atlantic and present reasons for this outcome and recommendations for future model parameterization.