优化训练数据场景,让气候模型模拟器更会举一反三。
Optimal scenario design for climate emulation

- 用可微分气候模型迭代优化训练数据,提升泛化能力。
- 仅用一个优化场景,性能超过六个传统路径的六倍训练。
- 适合需要高效建模气候系统响应的研究者。
随着深度学习在物理系统中的应用增多,提升泛化能力主要依赖嵌入物理约束的架构设计。然而,针对机器学习代理气候模型(模拟器),我们发现现有训练数据常用场景的结构多样性过低,限制了预测能力。本文提出优化训练数据本身以提升泛化性。通过可微分简单气候模型(SCM),计算模拟器损失对训练数据扰动的敏感度,迭代更新数据以最大化模拟器性能。在一个SCM上,仅用一个优化场景训练的模型,表现优于基于六条标准ScenarioMIP路径训练的模型。尽管训练数据量更小,该模型仍能有效区分温室气体与气溶胶等不同强迫源的物理行为,无需单因子实验。进一步验证表明,用SCM优化的场景驱动中等复杂度气候模型生成的数据,训练出的模拟器比使用ScenarioMIP输出更具预测力。结果表明,在全尺度气候模型计算资源受限的背景下,生成少量动态丰富的优化场景,其边际价值高于扩展传统排放路径数量。
原文摘要 · Abstract (English)
As deep learning for physical systems continues to grow in popularity, efforts to improve generalizability have primarily focused on designing architectures that embed physical constraints. However, for machine-learning surrogate climate models (emulators), we show that the low structural diversity in existing scenarios commonly used to generate training data places a ceiling on predictive skill. Here, we examine whether training datasets themselves can be optimized to improve generalization. We introduce a method to create datasets that produce emulators capable of generalizing to new, structurally different scenarios absent from the training data. We use a differentiable Simple Climate Model (SCM) to calculate the sensitivity of emulator loss to perturbations in the training data, iteratively updating the training data to maximize emulator skill. For an SCM, training on one scenario optimized in this fashion outperforms an emulator trained on six standard ScenarioMIP pathways. We achieve this higher predictive skill despite training on a smaller dataset, finding that our emulator successfully isolates distinct physical behaviors of different climate forcing agents (e.g., greenhouse gases vs. aerosols) without single-forcing runs. We then demonstrate that scenarios optimized using an SCM, when used to drive an intermediate-complexity climate model, produce a training dataset that yields a more skillful emulator than training on ScenarioMIP outputs. Our results suggest that, in the compute-constrained environment of running full-scale climate models, generating a small number of dynamically rich scenarios provides greater marginal value for emulation and characterizing system responses than expanding the suite of traditional emissions pathways.
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