A new intermediate coupled model for tropical climate variability and changes

The seminal Cane-Zebiak model has pioneered the dynamical simulations and predictions of the El Niño-Southern Oscillation (ENSO) phenomenon. Over the past four decades, climate models have improved substantially, but they remain struggling with simulating and predicting ENSO. Meanwhile, climate models have become so complex that understanding models themselves is nearly as elusive as understanding real world climate that they are designed to simulate. These challenges highlight the continuous need and utility of intermediate coupled models such as the Cane-Zebiak model.

In this work, we have developed a new intermediate coupled model for the tropical climate variability and changes. Compared to the Cane-Zebiak model that has an idealized rectangular ocean, this new model employs realistic ocean geometry across the globe. Furthermore, the subsurface ocean temperature anomaly in this model is derived from simulated thermocline variations with a new nonlocal parameterization developed from observations. This new model is able to realistically simulates both observed ENSO variability and long-term climate changes, and can be used to understand state-of-the-art climate models and their longstanding biases.