Interdecadal Pacific oscillation

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.

You can help Wikipedia by expanding it.This oceanography article is a stub.

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