Spherical Harmonic Optimal Transport: Application to Climate Models Comparisons

Fuente: arXiv
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Main Authors: Houédry, Pierre, Legheraba, Iskander, Buecher, Léo, Courty, Nicolas
Format: Preprint
Published: 2026
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author Houédry, Pierre
Legheraba, Iskander
Buecher, Léo
Courty, Nicolas
author_facet Houédry, Pierre
Legheraba, Iskander
Buecher, Léo
Courty, Nicolas
contents Optimal transport provides a powerful framework for comparing measures while respecting the geometry of their support, but comes with an expensive computational cost, hindering its potential application to real world use cases. On manifolds, convolutional algorithms based on the heat kernel have been proposed to alleviate this cost, but their theoretical properties remain largely unexplored. We establish that the heat kernel cost converges to the optimal transport cost as time vanishes in the balanced and unbalanced cases. In the specific case of the 2-sphere $\mathbb{S}^2$, we ensure that the associated Sinkhorn divergences retains the desirable geometric and analytic properties of classical optimal transport discrepancies. Moreover, we leverage the harmonic structure of the sphere to derive a fast Sinkhorn algorithm, requiring only $\mathcal{O}(n)$ memory and $\mathcal{O}(n^{3/2})$ time per iteration, with fully dense GPU-friendly operations. We validate its computational efficiency on synthetic data, and discuss its potential use in the evaluation of global climate models, providing both spatial and seasonal insights into models performances.
format Preprint
id arxiv_https___arxiv_org_abs_2605_18389
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Spherical Harmonic Optimal Transport: Application to Climate Models Comparisons
Houédry, Pierre
Legheraba, Iskander
Buecher, Léo
Courty, Nicolas
Machine Learning
Optimization and Control
Optimal transport provides a powerful framework for comparing measures while respecting the geometry of their support, but comes with an expensive computational cost, hindering its potential application to real world use cases. On manifolds, convolutional algorithms based on the heat kernel have been proposed to alleviate this cost, but their theoretical properties remain largely unexplored. We establish that the heat kernel cost converges to the optimal transport cost as time vanishes in the balanced and unbalanced cases. In the specific case of the 2-sphere $\mathbb{S}^2$, we ensure that the associated Sinkhorn divergences retains the desirable geometric and analytic properties of classical optimal transport discrepancies. Moreover, we leverage the harmonic structure of the sphere to derive a fast Sinkhorn algorithm, requiring only $\mathcal{O}(n)$ memory and $\mathcal{O}(n^{3/2})$ time per iteration, with fully dense GPU-friendly operations. We validate its computational efficiency on synthetic data, and discuss its potential use in the evaluation of global climate models, providing both spatial and seasonal insights into models performances.
title Spherical Harmonic Optimal Transport: Application to Climate Models Comparisons
topic Machine Learning
Optimization and Control
url https://arxiv.org/abs/2605.18389