Interannual to multidecadal timescale climate variations in the northeast Pacific

Analysis of five, long-term coastal air temperature records, reconstructed from tree ring growth patterns, indicate that the climate of the northeast Pacific Ocean has oscillated at three dominant timescales over the last 400 years: the well-known 2-8-yr El Nino-Southern Oscillation (ENSO) timescale , a 20-40-yr interdecadal timescale, and a 60-80-yr multidecadal timescale. The latter oscillation has been the dominant mode of air temperature varia bility along the west coast of North America over the last 400 years. Durin g this period, there have been conspicuous temporal modulations of the ENSO and the interdecadal signals. Low-frequency temperature oscillations at pe riods greater than 10 years in the northeast Pacific have been significantl y coherent and in-phase from southern California to British Columbia. Howev er, with the exception of the ENSO signal, higher-frequency variability has been weakly coherent along the west coast. Recent work suggests that the i nterdecadal oscillation is a worldwide phenomenon that relies on global-sca le air-sea interactions to explain its existence. Superimposed on this glob al pattern are basin-scale interactions that force regional variability in ocean climate.