Atlantic Pacemaker Simulations

A 10-member ensemble of CESM1 (1 degree spatial resolution) simulations in which time-evolving SST anomalies in the North Atlantic (5N-55N, with a linearly tapering buffer zone that extends to EQ and 60N, the Atlantic basin) are nudged to observations (NOAA Extended Reconstruction Sea Surface Temperature version 3: ERSSTv3b) during 1920-2013. In this way, the observed evolution of North Atlantic SSTs are maintained in each simulation, with the rest of the model's coupled climate system free to evolve.

Note that only the SST anomalies, not the total SST, are nudged to observations, maintaining the model's mean state, including any model biases. All external forcings are identical to the LENS, aside from stratospheric ozone. A second 10-member ensemble, identical to the first but with all forcings fixed at 1920 levels, is also available.