Tropical origins of North and South Pacific decadal variability
Article first published online: 10 OCT 2009
Copyright 2009 by the American Geophysical Union.
Geophysical Research Letters
Volume 36, Issue 19, October 2009
How to Cite
2009), Tropical origins of North and South Pacific decadal variability, Geophys. Res. Lett., 36, L19711, doi:10.1029/2009GL040313., and (
- Issue published online: 10 OCT 2009
- Article first published online: 10 OCT 2009
- Manuscript Accepted: 3 SEP 2009
- Manuscript Revised: 1 SEP 2009
- Manuscript Received: 6 AUG 2009
- Pacific Decadal Oscillation;
- El Niño–Southern Oscillation
 The origin of the Pacific Decadal Oscillation (PDO), the leading mode of sea surface temperature variability for the North Pacific, is a matter of considerable debate. One paradigm views the PDO as an independent mode centered in the North Pacific, while another regards it as a largely reddened response to El Niño-Southern Oscillation (ENSO) forcing from the tropics. We calculate the Southern Hemisphere equivalent of the PDO index based on the leading mode of sea surface temperature variability for the South Pacific and find that it adequately explains the spatial structure of the PDO in the North Pacific. A first-order autoregressive model forced by ENSO is used to reproduce the observed PDO indices in the North and South Pacific. These results highlight the strong similarity in Pacific decadal variability on either side of the equator and suggest it may best be viewed as a reddened response to ENSO.