用AI从大气环流状态重建欧洲气温降水,提升季节预报精度。
AI reconstruction of European weather from the Euro-Atlantic regimes
- 基于大气环流态指数,用非线性AI模型重建欧洲温湿异常。
- 当环流指数误差低于80%时,预报效果优于ECMWF的官方系统SEAS5。
- 可直接使用气候预测模型的环流指数,适合季节预报研究者。
我们提出一种非线性AI模型,基于欧亚大西洋天气环流(WR)指数,重建欧洲月平均气温与降水量异常。WR代表大气环流的周期性、准静止且持续的状态,对欧洲天气有显著影响,为亚季节至季节预报提供了可能。尽管已有大量研究关注WR与欧洲天气的相关性及其影响,但利用WR指数估算地表气候变量(如温度与降水)仍主要依赖线性方法,尚未充分探索。本研究提出的AI模型能够捕捉WR指数与欧洲地表温湿异常之间的复杂非线性关系。我们评估了模型在欧洲冬夏两季重建2米气温和总降水量异常的表现,并测试了不同数量的WR指数对重建效果的影响。结果表明,在WR指数均方相对误差低于80%的条件下,模型的季节重建性能优于欧洲中期天气预报中心(ECMWF)的运营系统SEAS5。作为实际应用展示,我们使用SEAS5预测的WR指数进行评估,发现模型表现略优或相当,证明了该方法在季节预报中的潜力。
原文摘要 · Abstract (English)
We present a non-linear AI-model designed to reconstruct monthly mean anomalies of the European temperature and precipitation based on the Euro-Atlantic Weather regimes (WR) indices. WR represent recurrent, quasi-stationary, and persistent states of the atmospheric circulation that exert considerable influence over the European weather, therefore offering an opportunity for sub-seasonal to seasonal forecasting. While much research has focused on studying the correlation and impacts of the WR on European weather, the estimation of ground-level climate variables, such as temperature and precipitation, from Euro-Atlantic WR remains largely unexplored and is currently limited to linear methods. The presented AI model can capture and introduce complex non-linearities in the relation between the WR indices, describing the state of the Euro-Atlantic atmospheric circulation and the corresponding surface temperature and precipitation anomalies in Europe. We discuss the AI-model performance in reconstructing the monthly mean two-meter temperature and total precipitation anomalies in the European winter and summer, also varying the number of WR used to describe the monthly atmospheric circulation. We assess the impact of errors on the WR indices in the reconstruction and show that a mean absolute relative error below 80% yields improved seasonal reconstruction compared to the ECMWF operational seasonal forecast system, SEAS5. As a demonstration of practical applicability, we evaluate the model using WR indices predicted by SEAS5, finding slightly better or comparable skill relative to the SEAS5 forecast itself. Our findings demonstrate that WR-based anomaly reconstruction, powered by AI tools, offers a promising pathway for sub-seasonal and seasonal forecasting.
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