Pacific decadal oscillation

Common card · No. 322631

The Pacific decadal oscillation (PDO) is a robust, recurring pattern of ocean-atmosphere climate variability centered over the mid-latitude Pacific basin. The PDO is detected as warm or cool surface waters in the Pacific Ocean, north of 20°N. During the past century, the amplitude of this climate pattern has varied irregularly at interannual-to-interdecadal time scales, meaning, time periods of a few years to as much as time periods of multiple decades. There is evidence of reversals in the prevailing polarity (meaning, changes in cool surface waters versus warm surface waters within the region) of the oscillation that occurred around 1925, 1947, and 1977. The last two reversals corresponded with dramatic shifts documented in salmon production regimes in the North Pacific Ocean. This climate pattern also affects coastal sea and continental surface air temperatures from Alaska to California. During a "warm", or "positive", phase, the west Pacific becomes cooler and part of the eastern ocean...

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