Impact of Data-Driven Eddy Parameterization on Climate State in an Idealized Coupled CESM Model

A new study led by Jia-Rui Shi explores how a data-driven eddy parameterization influences large-scale climate dynamics in a coupled climate model. By implementing the ZB20 eddy momentum parameterization in an idealized CESM configuration with MOM6 and CAM, the team found that the parameterized backscatter increases eddy kinetic energy, strengthens poleward ocean heat transport, and intensifies the overturning circulation in the Southern Hemisphere. These ocean adjustments produce a distinct dipolar sea surface temperature pattern, with mid-latitude cooling and high-latitude warming, and also affect the atmosphere through a compensating reduction in atmospheric heat transport and an equatorward shift of the mid-latitude jet. The results show how data-driven representations of ocean eddies can shape the mean climate state and provide insight for improving future climate models.