Evidence of quasi‐biennial oscillations in a general circulation model

Pulses with periods of nearly two years are known to influence weather and climate. The underlying mechanism of this phenomenon has remained elusive. In this report we show that the time series of air temperature, air pressure, and ocean temperature calculated in a coupled ocean‐atmosphere general circulation model display quasi‐biennial oscillations. The amplitude of the oscillation generally increases with latitude although its magnitude relative to the annual cycle decreases with latitude. The general circulation model we have studied does not incorporate the tropical stratosphere; this implies that tropospheric quasi‐biennial oscillations originate within the troposphere‐ocean system.