arXiv:2604.23045cs.LG2026-04

提出可微分框架dCLIMBA,提升气候模型降水偏差校正精度与泛化能力

A Differentiable Framework for Global Circulation Model Precipitation Bias Correction

  • 通过可微分参数化方法学习时空自适应偏差调整机制
  • 显著改善极端降水分布,上尾部分校正效果尤为突出
  • 模块化设计适合连接气候模型与实际影响评估,适用于新区域

全球气候模型(GCM)输出存在系统性偏差,限制其在区域规划中的直接应用,因此偏差校正是短期与长期影响评估的必要步骤。降水偏差校正尤其困难,因其非高斯分布、间歇性及重尾极端特征。传统统计方法难以从大数据中学习系统模式或泛化至新地点;而机器学习虽灵活,但结果不可预测且难以解释,限制了跨模型和跨区域的通用性。本文提出一种可微分偏差调整框架dCLIMBA,学习历史CMIP6模型输出与基于观测的Livneh数据集之间的时空自适应参数化偏差调整过程,而非直接生成修正后的降水。结果表明,该方法有效校正了极端降水的量级与分布,尤其在上尾部分表现优异;不同美国城市的降水分位数分布被良好再现,空间模式与广泛应用的LOCA2统计降尺度产品相当。此外,框架部分保留未来趋势,并在未见区域表现出有希望的边际偏差衰减。本工作提供了一种模块化、高效的偏差校正方案,可微分特性使其易于接入大气模型输出与地面影响分析。

原文摘要 · Abstract (English)

Systematic biases in General Circulation Model (GCM) outputs limit their direct applicability in regional planning, making bias correction a technically demanding but necessary step for both short-term and long-term impact assessment. Correcting precipitation is particularly challenging due to its non-Gaussian distribution, intermittent nature, and heavy-tailed extremes. However, traditional statistical bias-correction methods have limited ability to learn systematic patterns from large datasets or generalize to new locations. While machine learning (ML) provides greater flexibility, it can produce unpredictable and difficult-to-interpret results, limiting generalization across GCMs and locations. In this study, we propose a differentiable bias-adjustment framework called dCLIMBA, that learns a spatiotemporally adaptive parametric bias-adjustment procedure, rather than corrected precipitation directly, between historical CMIP6 model outputs and a gridded observation-based dataset, Livneh. Results demonstrate that the proposed method corrects the magnitude and distribution of extreme precipitation with particularly strong performance in the upper tail. The quantile distribution of precipitation was well reproduced across diverse U.S. cities, and spatial patterns were comparable to those from the widely used LOCA2 statistical downscaling product. In addition, the framework showed partial future trend preservation and promising attenuation of marginal biases in unseen regions. This work presents a modular and efficient bias-correction approach. The differentiable approach provides an easy-to-use option for connecting atmospheric-model outputs to on-the-ground impacts.

气候建模偏差校正可微分降水模拟

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