arXiv Machine Learning By Zhi-Song Liu, Helmi Toropainen, Ammar Kheder, Michael Boy

Climate downscaling with likelihood functional flow matching

Read the original on arXiv Machine Learning →

The paper introduces CD-FFM, a functional flow‑matching model that treats high‑resolution climate fields as continuous random fields, allowing queries at any location and resolution. Unlike grid‑based generative downscalers, CD‑FFM uses a pointwise velocity field and a noise prior fitted to the observed spectrum, giving each observation an exact likelihood. Applied to downscaling ERA5 temperature to 1 km over Fennoscandia, CD‑FFM improves the continuous ranked probability score by 27–31 % over regression and 12–18 % over a larger neural operator, while being about fifty times faster than a CorrDiff‑style diffusion model and also effective for precipitation.

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