On average once every four years, the Tropical Pacific warms considerably during events called El Ni\~no, leading to weather disruptions over many regions on Earth. Recent machine-learning approaches to El Ni\~no prediction, in particular Convolutional Neural Networks (CNNs), have shown a surprisingly high skill at relatively long lead times. In an attempt to understand this high skill, we here use data from distorted physics simulations with an intermediate complexity El Ni\~no model to determine what aspects of El Ni\~no physics are represented in a specific CNN-based classification method. We find that the CNN can adequately correct for distortions in the ocean adjustment processes, but that the machine-learning method has far more trouble to deal with distortions in upwelling feedback strength.
@article{arxiv.2206.03110,
title = {Physics captured by data-based methods in El Ni\~no prediction},
author = {G. Lancia and I. J. Goede and C. Spitoni and H. A. Dijkstra},
journal= {arXiv preprint arXiv:2206.03110},
year = {2024}
}