The influence of ENSO on the generation of decadal variability in the North Pacific

This diagnostic study explores the generation of decadal variability in the North Pacific resulting from the asymmetry of the El Nino - Southern Oscillation phenomenon and the nonlinearity of the atmospheric tropical - extratropical teleconnection. Nonlinear regression analysis of the North Pacific sea surface temperatures and atmospheric fields with respect to the ENSO index reveals that the main teleconnection centers shift between El Nino and La Nina years. This asymmetry in the ENSO response, together with the skewed probabilistic distribution of ENSO itself, may contribute to the generation of the long-term decadal variability of sea surface temperatures in the extratropical North Pacific. It is argued that this hypothesis may explain the significant variance of the observed Pacific decadal oscillation in the extratropics.