A Simplified Physics Atmosphere General Circulation Model for Idealized Climate Dynamics Studies

Simplified global atmospheric general circulation models are important tools for understanding basic climate dynamics and diagnosing more complete modeling systems. We have developed a simple, single-model framework with non-linear primitive equations that can be run via an interactive Python Jupyter notebook. This framework was developed as an educational tool for students to experiment with the model, as it is straightforward to prescribe a weak or strong background state, impose forcing, post-process data, and visualize results in one notebook. However, the model can also be used by experienced scientists for original research.

We have implemented three distinct innovations. First, the underlying dynamic core is entirely based in Python (as opposed to Fortran), making the model more accessible to both undergraduate and graduate students and easily multi-threaded for computational efficiency. The model can easily be run on a laptop without concerns such as compiler options or operating system, thus removing common technical barriers to access. Second, the background state can be specified within the same framework as “strong,” where the model equations have been modified into an anomaly model, or “weak,” where the original full-field model is relaxed to the background state. Third, the “forcing” is described in terms of prescribed latent heat release in the troposphere, the topography, and the background state. Forcing and resolution changes are easily implemented using one preprocessing script that supports a wide range of hypothesis-driven experimentation options. This presentation includes exploration of the model’s mean state, some sensitivity experiments, and an example diagnosis of ENSO teleconnections in a changing climate.