Njord: A Probabilistic Graph Neural Network for Ensemble Ocean Forecasting

Fuente: arXiv
Guardado en:
Detalles Bibliográficos
Autores principales: Holmberg, Daniel, Oskarsson, Joel, Wikingsson, Erik, Lindsten, Fredrik, Roos, Teemu
Formato: Preprint
Publicado: 2026
Materias:
Acceso en línea:
Etiquetas: Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
_version_ 1866913170923192320
author Holmberg, Daniel
Oskarsson, Joel
Wikingsson, Erik
Lindsten, Fredrik
Roos, Teemu
author_facet Holmberg, Daniel
Oskarsson, Joel
Wikingsson, Erik
Lindsten, Fredrik
Roos, Teemu
contents Ocean dynamics are inherently chaotic, yet existing machine learning ocean models produce only deterministic forecasts. We introduce Njord, a probabilistic data-driven model for ocean forecasting, applicable to both global and regional domains. Njord combines a deep latent variable framework with a graph neural network architecture, enabling sampling each forecast step in a single forward pass. We apply Njord globally at 0.25° resolution and regionally to the Baltic Sea at 2 km resolution. To scale to these large ocean grids we introduce K-means cluster meshes that adapt to irregular sea surface geometry. Experiments demonstrate strong performance on both domains compared to deterministic machine learning baselines, while also providing uncertainty estimates from the sampled ensemble forecasts. On the global OceanBench benchmark, Njord achieves the lowest errors on average across upper-ocean variables when evaluated against real-world observations, with the largest improvements in surface temperature prediction.
format Preprint
id arxiv_https___arxiv_org_abs_2605_15470
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Njord: A Probabilistic Graph Neural Network for Ensemble Ocean Forecasting
Holmberg, Daniel
Oskarsson, Joel
Wikingsson, Erik
Lindsten, Fredrik
Roos, Teemu
Machine Learning
Atmospheric and Oceanic Physics
Ocean dynamics are inherently chaotic, yet existing machine learning ocean models produce only deterministic forecasts. We introduce Njord, a probabilistic data-driven model for ocean forecasting, applicable to both global and regional domains. Njord combines a deep latent variable framework with a graph neural network architecture, enabling sampling each forecast step in a single forward pass. We apply Njord globally at 0.25° resolution and regionally to the Baltic Sea at 2 km resolution. To scale to these large ocean grids we introduce K-means cluster meshes that adapt to irregular sea surface geometry. Experiments demonstrate strong performance on both domains compared to deterministic machine learning baselines, while also providing uncertainty estimates from the sampled ensemble forecasts. On the global OceanBench benchmark, Njord achieves the lowest errors on average across upper-ocean variables when evaluated against real-world observations, with the largest improvements in surface temperature prediction.
title Njord: A Probabilistic Graph Neural Network for Ensemble Ocean Forecasting
topic Machine Learning
Atmospheric and Oceanic Physics
url https://arxiv.org/abs/2605.15470