1268 / 2024-09-20 21:36:19

Influence of SST-precipitation relationship over the equatorial western Pacific on simulation of the Madden-Julian Oscillation

Madden-Julian Oscillation,sea surface temperature,Precipitation,western Pacific

Capabilities of 43 models of the Coupled Model Intercomparison Project Phase 6 (CMIP6) to simulate the Madden-Julian Oscillation (MJO) were compared in this study. Models with higher MJO simulation skills reproduce organized large-scale convection more frequently over the equatorial western Pacific (EWP), suggesting that MJO simulations are tightly connected to organization of large-scale precipitation over the EWP. MJO simulation skills are not significantly correlated with the mean sea surface temperature (SST) over the EWP, but tightly connected to SST threshold for convection there. The top simulations exhibit lower SST threshold and more realistic SST-precipitation relationship over the EWP, suggesting that convection can be organized more easily and intensified more rapidly with the increasing SST in these simulations. Our results emphasize that reproducing the relationship between SST and large-scale precipitation over the EWP is critical to MJO simulations.