Abstract
The representation of easterly waves (EWs) over the east Pacific Ocean
(PEWs) in Coupled Model Intercomparison Project phase 6 (CMIP6)
simulations is examined. Models are assessed based on their ability of
reproducing PEW-related precipitation and its evolution. The leading
patterns reveal a large spread in the representation of PEW structure
and amplitude. A comparison of the models with the most realistic PEWs
with those with unrealistically weak PEW skill showed that the more
accurate simulations more effectively capture the mean state and EW
thermodynamic structures over the northeast Pacific. Particularly, good
models exhibit realistic PEW precipitation, weaker meridional mean state
humidity gradients, larger mean state precipitation over the Panama
Bight, and realistic convective moisture adjustment timescales. These
results underscore the importance of accurately representing the
sensitivity of PEW convection to anomalous moisture for the realistic
representation of the waves.