Decadal Variability

Decadal variability is climate variability on roughly 10 to 30 year timescales, expressed in basin-scale SST and circulation patterns rather than the seasonal cycle. The Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation are the dominant examples, both involving slow ocean heat redistribution coupled to atmospheric forcing. The ocean mixed layer integrates white-noise atmospheric forcing into red-noise low-frequency variability, which sets much of the decadal spectrum. Decadal modes modulate regional rainfall, fisheries recruitment, and the apparent rate of global warming over any single decade.