Moisture and wind effects of Rossby waves on Western Pacific Intertropical Convergence Zone breakdown events

Abstract This study investigates the mechanisms driving clustered convection and the breakdown of the Intertropical Convergence Zone (ITCZ) over the Western Pacific Warm Pool using high‐resolution cloud‐resolving simulations and machine‐learning sensitivity experiments. Results show that ITCZ breakdown episodes, marked by spatially homogeneous convection and weakened meridional moisture gradients, are triggered primarily by anomalous moisture advection linked to the equatorial Rossby‐wave activity. While large‐scale moisture advection regulates the background convective state strongly, it is the surface and low‐level meridional winds that dominate transitions between clustered and random convection. Simulations demonstrate that moisture alone can sustain convective clustering, but breakdown episodes are more persistent and widespread when coupled with southerly meridional advection. These findings confirm that wave‐driven advection acts as a regulatory mechanism, periodically disrupting convective clustering and reshaping the meridional moisture gradient. This modulation of organization by wave‐induced breakdown events is critical for understanding tropical convection variability and its implications for the climate system.