Coupled Ocean-Atmosphere Dynamics in a Machine Learning Earth System Model
This work addresses seasonal climate prediction for sectors like agriculture and energy, representing an incremental advance in applying machine learning to earth-system modeling.
The researchers tackled the problem of seasonal climate forecasting by developing the Ola model, an AI/ML coupled earth-system model, which successfully generated realistic El Niño/Southern Oscillation characteristics and showed initial forecasting skill comparable to existing models like SPEAR.
Seasonal climate forecasts are socioeconomically important for managing the impacts of extreme weather events and for planning in sectors like agriculture and energy. Climate predictability on seasonal timescales is tied to boundary effects of the ocean on the atmosphere and coupled interactions in the ocean-atmosphere system. We present the Ocean-linked-atmosphere (Ola) model, a high-resolution (0.25°) Artificial Intelligence/ Machine Learning (AI/ML) coupled earth-system model which separately models the ocean and atmosphere dynamics using an autoregressive Spherical Fourier Neural Operator architecture, with a view towards enabling fast, accurate, large ensemble forecasts on the seasonal timescale. We find that Ola exhibits learned characteristics of ocean-atmosphere coupled dynamics including tropical oceanic waves with appropriate phase speeds, and an internally generated El Niño/Southern Oscillation (ENSO) having realistic amplitude, geographic structure, and vertical structure within the ocean mixed layer. We present initial evidence of skill in forecasting the ENSO which compares favorably to the SPEAR model of the Geophysical Fluid Dynamics Laboratory.