Generative data-driven approaches for stochastic subgrid parameterizations in an idealized ocean model

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Hauptverfasser: Perezhogin, Pavel, Zanna, Laure, Fernandez-Granda, Carlos
Format: Preprint
Veröffentlicht: 2023
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author Perezhogin, Pavel
Zanna, Laure
Fernandez-Granda, Carlos
author_facet Perezhogin, Pavel
Zanna, Laure
Fernandez-Granda, Carlos
contents Subgrid parameterizations of mesoscale eddies continue to be in demand for climate simulations. These subgrid parameterizations can be powerfully designed using physics and/or data-driven methods, with uncertainty quantification. For example, Guillaumin and Zanna (2021) proposed a Machine Learning (ML) model that predicts subgrid forcing and its local uncertainty. The major assumption and potential drawback of this model is the statistical independence of stochastic residuals between grid points. Here, we aim to improve the simulation of stochastic forcing with generative models of ML, such as Generative adversarial network (GAN) and Variational autoencoder (VAE). Generative models learn the distribution of subgrid forcing conditioned on the resolved flow directly from data and they can produce new samples from this distribution. Generative models can potentially capture not only the spatial correlation but any statistically significant property of subgrid forcing. We test the proposed stochastic parameterizations offline and online in an idealized ocean model. We show that generative models are able to predict subgrid forcing and its uncertainty with spatially correlated stochastic forcing. Online simulations for a range of resolutions demonstrated that generative models are superior to the baseline ML model at the coarsest resolution.
format Preprint
id arxiv_https___arxiv_org_abs_2302_07984
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Generative data-driven approaches for stochastic subgrid parameterizations in an idealized ocean model
Perezhogin, Pavel
Zanna, Laure
Fernandez-Granda, Carlos
Atmospheric and Oceanic Physics
Subgrid parameterizations of mesoscale eddies continue to be in demand for climate simulations. These subgrid parameterizations can be powerfully designed using physics and/or data-driven methods, with uncertainty quantification. For example, Guillaumin and Zanna (2021) proposed a Machine Learning (ML) model that predicts subgrid forcing and its local uncertainty. The major assumption and potential drawback of this model is the statistical independence of stochastic residuals between grid points. Here, we aim to improve the simulation of stochastic forcing with generative models of ML, such as Generative adversarial network (GAN) and Variational autoencoder (VAE). Generative models learn the distribution of subgrid forcing conditioned on the resolved flow directly from data and they can produce new samples from this distribution. Generative models can potentially capture not only the spatial correlation but any statistically significant property of subgrid forcing. We test the proposed stochastic parameterizations offline and online in an idealized ocean model. We show that generative models are able to predict subgrid forcing and its uncertainty with spatially correlated stochastic forcing. Online simulations for a range of resolutions demonstrated that generative models are superior to the baseline ML model at the coarsest resolution.
title Generative data-driven approaches for stochastic subgrid parameterizations in an idealized ocean model
topic Atmospheric and Oceanic Physics
url https://arxiv.org/abs/2302.07984