Interdecadal Pacific Oscillation

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Annual variation of IPO since 1871 by Met Office. The positive phases are represented by positive index numbers; negative numbers represent negative phases.

The Interdecadal Pacific oscillation (IPO) is an oceanographic/meteorological phenomenon similar to the Pacific decadal oscillation (PDO), but occurring in a wider area of the Pacific. While the PDO occurs in mid-latitudes of the Pacific Ocean in the northern hemisphere, the IPO stretches from the southern hemisphere into the northern hemisphere.

The period of oscillation is roughly 15-30 years. Positive phases of the IPO are characterized by a warmer than average tropical Pacific and cooler than average northern Pacific. Negative phases are characterized by an inversion of this pattern, with cool tropics and warm northern regions.[1]

The IPO had positive phases (southeastern tropical Pacific warm) from 1922 to 1946 and 1978 to 1998, and a negative phase between 1947 and 1976.[2]


  1. ^ "Climatology - Interdecadal Pacific Oscillation (IPO)". Retrieved 2018-04-26.
  2. ^ Salinger, M.J.; Renwick, J.A.; Mullan, A.B. (2001). "Interdecadal Pacific Oscillation and South Pacific Climate". International Journal of Climatology. 21 (14): 1705–1721. Bibcode:2001IJCli..21.1705S. doi:10.1002/joc.691.