Robust longitudinally-variable responses of the ITCZ to a myriad of
climate forcings
- Alyssa R. Atwood,
- Aaron Donohoe,
- David S. Battisti,
- Xiaojuan Liu,
- Francesco S.R. Pausata
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.