The complex nature of El Nino - Southern Oscillation (ENSO) is often simplified
through the use of conceptual models, each of which offers a different
perspective on the ocean-atmosphere feedbacks underpinning the ENSO
cycle. One theory, the unified oscillator, combines a variety of conceptual
frameworks in the form of a coupled system of delay differential equations.
The system produces a self-sustained oscillation on interannual timescales.
While the unified oscillator is assumed to provide a more complete conceptual
framework of ENSO behaviors than the models it incorporates, its formulation
and performance have not been systematically assessed. This paper investigates
the accuracy of the unified oscillator through its ability to replicate
the ENSO cycle modeled by flux-forced output from the Australian Community
Climate and Earth System Simulator Ocean Model (ACCESS-OM). The
anomalous sea surface temperature equation reproduces the main features of
the corresponding tendency modeled by ACCESS-OM reasonably well. However,
the remaining equations - for the thermocline depth anomaly and zonal
wind stress anomalies - are unable to accurately replicate the corresponding
tendencies in ACCESS-OM. Modifications to the unified oscillator, including
a diagnostic form of the zonal wind stress anomaly equations, improve its
ability to emulate simulated ENSO tendencies. Despite these improvements,
the unified oscillator model is less adept than the delayed oscillator model
it incorporates in capturing ENSO behavior in ACCESS-OM, bringing into
question its usefulness as a unifying ENSO framework.