Climate Variability & Change
Working Group CVCWG
CESM1 Pacific Pacemaker Ensemble
A 20-member ensemble of CESM1 (1 degree spatial resolution) simulations in which time-evolving SST anomalies in the eastern
tropical Pacific (10S–10N, 160–90W, with a linearly tapering buffer zone that extends to 20S and 20N, 180W to the American coast)
are nudged to observations (NOAA Extended Reconstruction Sea Surface Temperature version 3: ERSSTv3b) during 1920-2013. In this
way, the observed evolution of ENSO is maintained in each simulation (i.e., ENSO is the pacemaker), 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. Further details are provided in the two papers below:
- Deser, C., I. R. Simpson, K. A. McKinnon and A. S. Phillips, 2017: The Northern Hemisphere extra-tropical atmospheric
circulation response to ENSO: How well do we know it and how do we evaluate models accordingly? J. Climate, 30, 5059-5082,
- Deser, C., R. Guo and F. Lehner, 2017: The relative contributions of tropical Pacific sea surface temperatures and atmospheric
internal variability to the recent global warming hiatus. Geophys. Res. Lett., doi: 10.1002/2017GL074273.
We kindly ask that you reference one of these papers and acknowledge the CVCWG when presenting results based on the CESM1 Pacemaker
Ensemble in either oral and written form.
The CESM1 Pacific Pacemaker 20-member ensemble is available from the HPSS accessed from the NCAR machine cheyenne at
/CCSM/csm/PAC-PACEMAKER. If you do not have access to cheyenne you can contact the
CVCWG liaisons for assistance.