Application of MJO simulation diagnostics to CMIP5 climate models : MJO indices and Process‐oriented diagnosis

Abstract:

The MJO simulation diagnostics developed by MJO Working Group (MJOWG) applied to 36 Coupled Model Intercomparison Project phase 5 (CMIP5) models and the several MJO indices formulated to capture the prominent features of the MJO with a single quantity. Most CMIP5 models underestimate the MJO amplitude and eastward propagation, especially in OLR signal. And most CMIP5 models simulate fast MJO propagation speed compared to observation. Three MJO process-oriented diagnostics proposed so far are applied to 22 CMIP5 models to find the MJO favorable parameterization of physical process in CMIP5 models. The RH-metric that indicates the sensitivity of simulated convection to low level environmental moisture is relatively well correlated with MJO amplitude and eastward propagation of precipitation and wind signal. The GEF-metric that indicates the strength of column-integrated longwave radiative heating due to cloud-radiation interaction is relatively well correlated with MJO amplitude and eastward propagation of precipitation signal. The NGMS-metric that indicates the atmospheric stability controlled by strength of exporting moist static energy out of the column in convecting atmosphere is relatively well negative correlated with not only eastward propagating speed of precipitation and wind signal but also MJO amplitude and eastward propagation of precipitation signal.