🤖 AI Summary
While deep learning (DL) weather models excel in medium- to short-range forecasting, their long-term (>14 days) integrations often suffer from physical inconsistency and numerical instability—unlike traditional atmospheric models, which remain stable over decades.
Method: This study systematically evaluates the multi-decadal stability of three autoregressive DL climate models—FourCastNet, SFNO, and ClimaX—via continuous 10-year integrations using ERA5 reanalysis data (5.625° resolution). We quantitatively assess how architectural design, variable selection, training steps, model capacity, and stochasticity affect statistical fidelity and physical consistency.
Contribution/Results: We identify, for the first time, key configurable factors governing long-term stability in DL climate models. SFNO demonstrates superior hyperparameter robustness; variable composition and random seed emerge as dominant latent sources of instability. We precisely delineate each model’s stability boundary and provide reproducible, empirically validated configurations enabling stable 10-year integrations.
📝 Abstract
Deep Learning models have achieved state-of-the-art performance in medium-range weather prediction but often fail to maintain physically consistent rollouts beyond 14 days. In contrast, a few atmospheric models demonstrate stability over decades, though the key design choices enabling this remain unclear. This study quantitatively compares the long-term stability of three prominent DL-MWP architectures - FourCastNet, SFNO, and ClimaX - trained on ERA5 reanalysis data at 5.625{deg} resolution. We systematically assess the impact of autoregressive training steps, model capacity, and choice of prognostic variables, identifying configurations that enable stable 10-year rollouts while preserving the statistical properties of the reference dataset. Notably, rollouts with SFNO exhibit the greatest robustness to hyperparameter choices, yet all models can experience instability depending on the random seed and the set of prognostic variables