CESM1 AMV idealized experiments

To gain insight into the atmospheric teleconnections associated with the AMV, we perform idealized experiments using Community Earth System Model version 1 (CESM1) in which North Atlantic SSTs are restored to a time-independent spatial pattern corresponding to an estimate of the internal component of the observed AMV anomaly (see Ruprich-Robert et al. (2017) for more details). CESM1 uses nominal 1deg horizontal resolution in all its components.

Because we aim to assess the effects of internal variability, all experiments use pre-industrial conditions where external forcings are kept fixed at levels corresponding to either calendar year 1850. The restoring is fully applied between 8-65N in the North Atlantic, linearly diminishing to zero within the 8deg buffer zones at the northern and southern boundaries, so that the constrained region is confined between the Equator and 73N.