Universal Diffusion-Based Probabilistic Downscaling

Fuente: arXiv
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Main Authors: Molinaro, Roberto, Siegenheim, Niall, Martin, Henry, Frey, Mark, Poulsen, Niels, Seitz, Philipp, Gabler, Marvin Vincent
Format: Preprint
Published: 2026
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author Molinaro, Roberto
Siegenheim, Niall
Martin, Henry
Frey, Mark
Poulsen, Niels
Seitz, Philipp
Gabler, Marvin Vincent
author_facet Molinaro, Roberto
Siegenheim, Niall
Martin, Henry
Frey, Mark
Poulsen, Niels
Seitz, Philipp
Gabler, Marvin Vincent
contents We introduce a universal diffusion-based downscaling framework that lifts deterministic low-resolution weather forecasts into probabilistic high-resolution predictions without any model-specific fine-tuning. A single conditional diffusion model is trained on paired coarse-resolution inputs (~25 km resolution) and high-resolution regional reanalysis targets (~5 km resolution), and is applied in a fully zero-shot manner to deterministic forecasts from heterogeneous upstream weather models. Focusing on near-surface variables, we evaluate probabilistic forecasts against independent in situ station observations over lead times up to 90 h. Across a diverse set of AI-based and numerical weather prediction (NWP) systems, the ensemble mean of the downscaled forecasts consistently improves upon each model's own raw deterministic forecast, and substantially larger gains are observed in probabilistic skill as measured by CRPS. These results demonstrate that diffusion-based downscaling provides a scalable, model-agnostic probabilistic interface for enhancing spatial resolution and uncertainty representation in operational weather forecasting pipelines.
format Preprint
id arxiv_https___arxiv_org_abs_2602_11893
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Universal Diffusion-Based Probabilistic Downscaling
Molinaro, Roberto
Siegenheim, Niall
Martin, Henry
Frey, Mark
Poulsen, Niels
Seitz, Philipp
Gabler, Marvin Vincent
Machine Learning
We introduce a universal diffusion-based downscaling framework that lifts deterministic low-resolution weather forecasts into probabilistic high-resolution predictions without any model-specific fine-tuning. A single conditional diffusion model is trained on paired coarse-resolution inputs (~25 km resolution) and high-resolution regional reanalysis targets (~5 km resolution), and is applied in a fully zero-shot manner to deterministic forecasts from heterogeneous upstream weather models. Focusing on near-surface variables, we evaluate probabilistic forecasts against independent in situ station observations over lead times up to 90 h. Across a diverse set of AI-based and numerical weather prediction (NWP) systems, the ensemble mean of the downscaled forecasts consistently improves upon each model's own raw deterministic forecast, and substantially larger gains are observed in probabilistic skill as measured by CRPS. These results demonstrate that diffusion-based downscaling provides a scalable, model-agnostic probabilistic interface for enhancing spatial resolution and uncertainty representation in operational weather forecasting pipelines.
title Universal Diffusion-Based Probabilistic Downscaling
topic Machine Learning
url https://arxiv.org/abs/2602.11893