Simulation of the Phase and Amplitude of the Madden-Julian Oscillation in Different Versions of the INM RAS Climate Model

The RMM (Real-time Multivariate MJO) index is used to evaluate the skill of simulating the amplitude and phase of the Madden-Julian Oscillation (MJO) for various versions of the INM RAS (Institute of Numerical Mathematics of the Russian Academy of Sciences) climate model. The model results are compared to the other CMIP6 climate models and ERA-Interim reanalysis. It has been shown that all the versions of the INM RAS model correctly reproduce the MJO amplification in the Northern Hemisphere winter, but significantly underestimate the amplitude of the oscillations as compared to the reanalysis data. The models correctly reproduce the eastward propagation of the MJO, but the INM-CM5-0 and INM-CM6-L are unable to simulate the crossing of Indonesia by the convective center of MJO. In the INM-CM6-L*, the MJO trajectory is better simulated as compared to previous versions, and the amplitude for the individual MJO events is consistent with the reanalysis data. However, the MJO events in the INM-CM6-L* make up only about 30% of their total number according to the reanalysis data over the period 1980-2014.