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Geophysical Research Letters· 2026Q1

Probing Atmospheric Gravity‐Wave‐Relevant Representations in a Weather Foundation Model via Multi‐Method Fine‐Tuning

Yanan Guo, Junqiang Song, Chuanfeng Zhao, Xiaoqun Cao et al.

Short summary

A weather foundation model (Aurora) shows pretraining benefits for predicting gravity-wave momentum fluxes, particularly zonal flux (38.9% vs. 41.6% normalized error with FISH + TADP vs. random control), with a 1% parameter fine-tuning recovering significant skill.

AI-generated from the title and abstract; the full text is not read.

Key points

  • Pretraining in the Aurora weather foundation model shows a benefit for predicting gravity-wave momentum fluxes.
  • The zonal flux prediction improved with parameter-efficient fine-tuning methods (e.g., FISH + TADP) compared to random initialization (38.9% vs. 41.6% normalized error).
  • Meridional flux prediction remained difficult across all methods (60%-80% NRMSE).
  • The pretraining benefit was level-dependent, with significant gains at 200-300 hPa but minimal gains at 50 hPa.
  • Fine-tuning approximately 1% of parameters recovered a significant portion of the skill seen with full fine-tuning, indicating regularization from the frozen backbone.

AI-generated from the title and abstract; the full text is not read.

Abstract

Abstract Weather foundation models pretrained on reanalysis data may encode subgrid‐scale physics beyond their forecasting objectives. Using Aurora, we probe this with a multi‐method fine‐tuning framework: agreement across structurally different adaptation strategies signals shared backbone information, while a matched randomly initialized control isolates pretraining's contribution. We evaluate six methods (0.5%–100% of trainable parameters) for predicting ERA5‐resolved, T21‐filtered gravity‐wave momentum fluxes (313–1,820 km). Evidence for a pretraining benefit is strongest for the zonal flux : several parameter‐efficient methods outperform random initialization, most clearly FISH + TADP (38.9% vs. 41.6% normalized error, = 0.007). The meridional flux remains hard for all methods (NRMSE 60%–80%). The benefit is level‐dependent: 11–14 percentage points at 200–300 hPa but only 0.2 at 50 hPa. Approximately 1% of parameters recover part of full‐fine‐tuning skill (38.9% vs. 31.8%), indicating regularization by the frozen backbone.

The authors' abstract, as published at the source. Geophysical Research Letters, 2026 · DOI ↗

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Field: Atmospheric Science

Atmospheric ScienceEarth and Planetary Sciences