用潜在空间约束生成更多气候数据,提升模型泛化能力。
Latent-Constrained Conditional VAEs for Augmenting Large-Scale Climate Ensembles
- 通过锚点位置约束潜空间,确保不同气候模拟间的一致性。
- 加入5个以上模拟后增益减弱,潜空间邻居距离影响重建质量。
- 适合需要海量气候数据但计算成本高的研究者使用。
大规模气候模型集合计算代价高昂,但许多下游分析需更多统计一致的时空气候变量实现。本文研究一种生成方法,从有限的可用模拟中转移跨集合结构信息以生成新实现。基于十组独立再分析数据(ERA5)的月度地表温度时间序列,发现联合训练的普通条件变分自编码器(CVAE)会产生碎片化潜空间,无法泛化到未见集合成员。为此提出潜空间约束的条件变分自编码器(LC-CVAE),在少数共享地理“锚点”位置强制潜嵌入跨实现实体一致性。随后在潜空间使用多输出高斯过程回归预测新实现中未采样位置的潜坐标,并解码生成完整时间序列场。实验与消融分析表明:(i) 单一实现实现训练不稳定;(ii) 引入约五个实现实现后收益递减;(iii) 空间覆盖与重建质量存在权衡,与潜空间平均邻近距离密切相关。
原文摘要 · Abstract (English)
Large climate-model ensembles are computationally expensive; yet many downstream analyses would benefit from additional, statistically consistent realizations of spatiotemporal climate variables. We study a generative modeling approach for producing new realizations from a limited set of available runs by transferring structure learned across an ensemble. Using monthly near-surface temperature time series from ten independent reanalysis realizations (ERA5), we find that a vanilla conditional variational autoencoder (CVAE) trained jointly across realizations yields a fragmented latent space that fails to generalize to unseen ensemble members. To address this, we introduce a latent-constrained CVAE (LC-CVAE) that enforces cross-realization homogeneity of latent embeddings at a small set of shared geographic 'anchor' locations. We then use multi-output Gaussian process regression in the latent space to predict latent coordinates at unsampled locations in a new realization, followed by decoding to generate full time series fields. Experiments and ablations demonstrate (i) instability when training on a single realization, (ii) diminishing returns after incorporating roughly five realizations, and (iii) a trade-off between spatial coverage and reconstruction quality that is closely linked to the average neighbor distance in latent space.
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