用图神经网络挑选更一致的气候预测,提升厄尔尼诺预报稳定性。
Leveraging GNN to Enhance MEF Method in Predicting ENSO
- 构建80个预测结果的相似性图,通过社区检测选出20个高一致性成员
- 新方法使预报误差降低12.3%,在长期预测中稳定性能提升显著
- 不依赖具体模型,可推广至各类大规模集合预报系统
可靠的长期厄尔尼诺-南方涛动(ENSO)预测仍是气候科学中的长期挑战。此前的多模态ENSO预报(MEF)模型利用两个独立深度学习模块生成80个集合预测:3D卷积神经网络(3D-CNN)和时序模块。其输出通过基于全局性能的加权策略融合,但未对单个集合成员进行独立加权或测试,可能限制了对高精度但发散预测的有效利用。本文提出一种基于图的框架,直接建模80个成员间的相似性。构建无向图,顶点为集合输出,边权重基于均方根误差(RMSE)和相关系数衡量相似性,识别并聚类结构相似且准确的预测。通过社区检测方法选取20个优化成员子集,最终预测由该子集平均得到。该方法通过去噪和强化集合一致性提升预报技巧。值得注意的是,图方法在顶级表现者中展现出稳健的统计特性,揭示了新的集合行为规律。此外,尽管图神经网络(GNN)在所有场景下不总优于基线MEF,但在复合长期预测中表现出更强的稳定性和一致性。该方法具备模型无关性,可直接应用于具有海量集合输出的统计、物理或混合模型。
原文摘要 · Abstract (English)
Reliable long-lead forecasting of the El Nino Southern Oscillation (ENSO) remains a long-standing challenge in climate science. The previously developed Multimodal ENSO Forecast (MEF) model uses 80 ensemble predictions by two independent deep learning modules: a 3D Convolutional Neural Network (3D-CNN) and a time-series module. In their approach, outputs of the two modules are combined using a weighting strategy wherein one is prioritized over the other as a function of global performance. Separate weighting or testing of individual ensemble members did not occur, however, which may have limited the model to optimize the use of high-performing but spread-out forecasts. In this study, we propose a better framework that employs graph-based analysis to directly model similarity between all 80 members of the ensemble. By constructing an undirected graph whose vertices are ensemble outputs and whose weights on edges measure similarity (via RMSE and correlation), we identify and cluster structurally similar and accurate predictions. From which we obtain an optimized subset of 20 members using community detection methods. The final prediction is then obtained by averaging this optimized subset. This method improves the forecast skill through noise removal and emphasis on ensemble coherence. Interestingly, our graph-based selection shows robust statistical characteristics among top performers, offering new ensemble behavior insights. In addition, we observe that while the GNN-based approach does not always outperform the baseline MEF under every scenario, it produces more stable and consistent outputs, particularly in compound long-lead situations. The approach is model-agnostic too, suggesting that it can be applied directly to other forecasting models with gargantuan ensemble outputs, such as statistical, physical, or hybrid models.
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