El Nino and the delayed action oscillator

We study the dynamics of El Nino using the model of a delayed-action oscillator. Topics such as the influence of the annual cycle, global warming, stochastic influences due to weather conditions and off-equatorial heat-sinks are discussed using only modest analytical and numerical resources. The delayed-action oscillator allows for a pedagogical introduction to the science of El Nino and La Nina and avoids the need for large-scale computing resources normally associated with much more sophisticated coupled atmosphere-ocean general circulation models. (C) 2007 American Association of Physics Teachers.