Calibration of a neural network ocean closure for improved mean state and variability

Fuente: arXiv
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Autores principales: Perezhogin, Pavel, Adcroft, Alistair, Zanna, Laure
Formato: Preprint
Publicado: 2026
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author Perezhogin, Pavel
Adcroft, Alistair
Zanna, Laure
author_facet Perezhogin, Pavel
Adcroft, Alistair
Zanna, Laure
contents Global ocean models exhibit biases in the mean state and variability, particularly at coarse resolution, where mesoscale eddies are unresolved. To address these biases, parameterization coefficients are typically tuned ad hoc. Here, we formulate parameter tuning as a calibration problem using Ensemble Kalman Inversion (EKI). We optimize parameters of a neural network parameterization of mesoscale eddies in two idealized ocean models at coarse resolution. The calibrated parameterization reduces errors by factors of 1.7-3.3 in the time-averaged fluid interfaces and their variability compared to the unparameterized model, depending on the metric and configuration. The EKI method is robust to noise in time-averaged statistics arising from chaotic ocean dynamics. Furthermore, we propose an efficient calibration protocol that bypasses integration to statistical equilibrium by carefully choosing an initial condition. These results demonstrate that systematic calibration can substantially improve coarse-resolution ocean simulations and provide a practical pathway for reducing biases in global ocean models.
format Preprint
id arxiv_https___arxiv_org_abs_2604_06398
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Calibration of a neural network ocean closure for improved mean state and variability
Perezhogin, Pavel
Adcroft, Alistair
Zanna, Laure
Atmospheric and Oceanic Physics
Machine Learning
Computational Physics
Global ocean models exhibit biases in the mean state and variability, particularly at coarse resolution, where mesoscale eddies are unresolved. To address these biases, parameterization coefficients are typically tuned ad hoc. Here, we formulate parameter tuning as a calibration problem using Ensemble Kalman Inversion (EKI). We optimize parameters of a neural network parameterization of mesoscale eddies in two idealized ocean models at coarse resolution. The calibrated parameterization reduces errors by factors of 1.7-3.3 in the time-averaged fluid interfaces and their variability compared to the unparameterized model, depending on the metric and configuration. The EKI method is robust to noise in time-averaged statistics arising from chaotic ocean dynamics. Furthermore, we propose an efficient calibration protocol that bypasses integration to statistical equilibrium by carefully choosing an initial condition. These results demonstrate that systematic calibration can substantially improve coarse-resolution ocean simulations and provide a practical pathway for reducing biases in global ocean models.
title Calibration of a neural network ocean closure for improved mean state and variability
topic Atmospheric and Oceanic Physics
Machine Learning
Computational Physics
url https://arxiv.org/abs/2604.06398