Stationarity of the Tropical Pacific Teleconnection to North America in CMIP 5 / PMIP 3 1 Model Simulations

The temporal stationarity of the teleconnection between the tropical Pacific Ocean and 24 North America (NA) is analyzed in atmosphere-only, and coupled last-millennium, historical, 25 and control runs from the Coupled Model Intercomparison Project Phase 5 (CMIP5) data 26 archive. The teleconnection, defined as the correlation between December-January-February 27 (DJF) tropical Pacific sea surface temperatures (SSTs) and DJF 200mb geopotential height, is 28 found to be non-stationary on multidecadal timescales. There are significant changes in the 29 spatial features of the teleconnection over NA in continuous 56-year segments of the last30 millennium and control simulations. Analysis of atmosphere-only simulations forced with 31 observed SSTs indicates that atmospheric noise cannot account for the temporal variability of the 32 teleconnection, which instead is likely explained by the strength of, and multi-decadal changes 33 in, tropical Pacific Ocean variability. These results have implications for teleconnection-based 34 analyses of model fidelity in simulating precipitation, as well as any reconstruction and 35 forecasting efforts that assume stationarity of the observed teleconnection. 36 37 38 39 40 41 42 43 44 45 46