Evaluation of Equatorial Westerly Wind Events in the Pacific Ocean in CMIP6 Models

Intraseasonal westerly wind events (WWEs) are anomalously strong, long-lasting westerlies over the Indian and Pacific Oceans that can force oceanic waves, such as Kelvin and Rossby waves. These oceanic waves are important for regulating larger-scale phenomena such as ENSO and the MJO. This work examines the fidelity of WWEs over the Pacific Ocean in several CMIP6 simulations as well as two non-CMIP6 simulations (CESM2 and E3SM) compared to observations. WWEs are identified using equatorially averaged and intraseasonally filtered (5-90 day) daily zonal wind stress duration, zonal extent, and intensity criteria. While the simulations correctly place most of their WWEs in the west Pacific, the WWEs are skewed westward and occur less frequently than in observations. The simulated WWEs tend to last longer but are weaker and more zonally confined than observed WWEs. The spatiotemporal evolution of simulated WWEs appears to be linked to the MJO or convectively coupled equatorial Rossby waves depending on the fidelity of the MJO in each simulation.