Adjoint-based online learning of two-layer quasi-geostrophic baroclinic turbulence

Fuente: arXiv
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Autori principali: Yan, Fei Er, Frezat, Hugo, Sommer, Julien Le, Mak, Julian, Otness, Karl
Natura: Preprint
Pubblicazione: 2024
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author Yan, Fei Er
Frezat, Hugo
Sommer, Julien Le
Mak, Julian
Otness, Karl
author_facet Yan, Fei Er
Frezat, Hugo
Sommer, Julien Le
Mak, Julian
Otness, Karl
contents For reasons of computational constraint, most global ocean circulation models used for Earth System Modeling still rely on parameterizations of sub-grid processes, and limitations in these parameterizations affect the modeled ocean circulation and impact on predictive skill. An increasingly popular approach is to leverage machine learning approaches for parameterizations, regressing for a map between the resolved state and missing feedbacks in a fluid system as a supervised learning task. However, the learning is often performed in an `offline' fashion, without involving the underlying fluid dynamical model during the training stage. Here, we explore the `online' approach that involves the fluid dynamical model during the training stage for the learning of baroclinic turbulence and its parameterization, with reference to ocean eddy parameterization. Two online approaches are considered: a full adjoint-based online approach, related to traditional adjoint optimization approaches that require a `differentiable' dynamical model, and an approximately online approach that approximates the adjoint calculation and does not require a differentiable dynamical model. The online approaches are found to be generally more skillful and numerically stable than offline approaches. Others details relating to online training, such as window size, machine learning model set up and designs of the loss functions are detailed to aid in further explorations of the online training methodology for Earth System Modeling.
format Preprint
id arxiv_https___arxiv_org_abs_2411_14106
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Adjoint-based online learning of two-layer quasi-geostrophic baroclinic turbulence
Yan, Fei Er
Frezat, Hugo
Sommer, Julien Le
Mak, Julian
Otness, Karl
Atmospheric and Oceanic Physics
Machine Learning
Fluid Dynamics
For reasons of computational constraint, most global ocean circulation models used for Earth System Modeling still rely on parameterizations of sub-grid processes, and limitations in these parameterizations affect the modeled ocean circulation and impact on predictive skill. An increasingly popular approach is to leverage machine learning approaches for parameterizations, regressing for a map between the resolved state and missing feedbacks in a fluid system as a supervised learning task. However, the learning is often performed in an `offline' fashion, without involving the underlying fluid dynamical model during the training stage. Here, we explore the `online' approach that involves the fluid dynamical model during the training stage for the learning of baroclinic turbulence and its parameterization, with reference to ocean eddy parameterization. Two online approaches are considered: a full adjoint-based online approach, related to traditional adjoint optimization approaches that require a `differentiable' dynamical model, and an approximately online approach that approximates the adjoint calculation and does not require a differentiable dynamical model. The online approaches are found to be generally more skillful and numerically stable than offline approaches. Others details relating to online training, such as window size, machine learning model set up and designs of the loss functions are detailed to aid in further explorations of the online training methodology for Earth System Modeling.
title Adjoint-based online learning of two-layer quasi-geostrophic baroclinic turbulence
topic Atmospheric and Oceanic Physics
Machine Learning
Fluid Dynamics
url https://arxiv.org/abs/2411.14106