Abstract

We evaluate the longitudinal variation in meridional shifts of the tropical rainband in response to natural and anthropogenic forcings using a large suite of coupled climate model simulations. We find that the energetic framework of the zonal mean Hadley cell is generally not useful for characterizing shifts of the rainband at regional scales, regardless of the characteristics of the forcing. Forcings with large hemispheric asymmetry such as extratropical volcanic forcing and meltwater forcing give rise to robust zonal mean shifts of the rainband, however the direction and magnitude of the shift varies strongly as a function of longitude. Even the Pacific rainband doesn't shift uniformly under any forcing considered. Forcings with weak hemispheric asymmetry such as CO and mid-Holocene forcing give rise to zonal mean shifts that are small or absent, but the rainband does shift regionally in coherent ways across models that may have important dynamical consequences.