arXiv:2507.16219physics.ao-phcs.AI2025-07被引 1

用贝叶斯深度学习提升对流初生预报的不确定性估计,效果优于传统方法。

Bayesian Deep Learning for Convective Initiation Nowcasting Uncertainty Estimation

  • 采用初始权重集成+MC dropout生成多解,更充分覆盖假设空间。
  • 该方法在0-1小时对流初生预报中校准度最好,误差分离能力最强。
  • 适合需要高置信度风险评估的短临天气预警场景。

本研究基于GOES-16卫星红外观测数据,评估了五种近期提出的贝叶斯深度学习方法在0-1小时对流初生(CI)临近预报中的概率与不确定性预测表现,对比了确定性残差网络(ResNet)基线。通过校准程度及不确定性对大小误差案例的区分能力评估不确定性。多数贝叶斯方法优于确定性ResNet,其中初始权重集成+蒙特卡洛(MC)丢弃法表现最优,其通过训练起始权重不同且推理时启用丢弃,生成多解以更全面采样假设空间。贝叶斯ResNet集成在更长预报时效下表现劣于确定性ResNet,可能源于参数量过大导致优化困难。为此引入贝叶斯-MOPED(MOdel Priors with Empirical Bayes using Deep neural network)ResNet集成,通过约束假设搜索靠近确定性ResNet解,提升了预报技能。所有贝叶斯方法均表现出良好校准性和误差分离能力。案例分析显示,在晴空区域选定的对流事件中,初始权重集成+MC丢弃法优于贝叶斯-MOPED集成和确定性ResNet;但在无对流发生的晴空及砧状云区域,其泛化性能低于确定性ResNet和贝叶斯-MOPED集成。

原文摘要 · Abstract (English)

This study evaluated the probability and uncertainty forecasts of five recently proposed Bayesian deep learning methods relative to a deterministic residual neural network (ResNet) baseline for 0-1 h convective initiation (CI) nowcasting using GOES-16 satellite infrared observations. Uncertainty was assessed by how well probabilistic forecasts were calibrated and how well uncertainty separated forecasts with large and small errors. Most of the Bayesian deep learning methods produced probabilistic forecasts that outperformed the deterministic ResNet, with one, the initial-weights ensemble + Monte Carlo (MC) dropout, an ensemble of deterministic ResNets with different initial weights to start training and dropout activated during inference, producing the most skillful and well-calibrated forecasts. The initial-weights ensemble + MC dropout benefited from generating multiple solutions that more thoroughly sampled the hypothesis space. The Bayesian ResNet ensemble was the only one that performed worse than the deterministic ResNet at longer lead times, likely due to the challenge of optimizing a larger number of parameters. To address this issue, the Bayesian-MOPED (MOdel Priors with Empirical Bayes using Deep neural network) ResNet ensemble was adopted, and it enhanced forecast skill by constraining the hypothesis search near the deterministic ResNet hypothesis. All Bayesian methods demonstrated well-calibrated uncertainty and effectively separated cases with large and small errors. In case studies, the initial-weights ensemble + MC dropout demonstrated better forecast skill than the Bayesian-MOPED ensemble and the deterministic ResNet on selected CI events in clear-sky regions. However, the initial-weights ensemble + MC dropout exhibited poorer generalization in clear-sky and anvil cloud regions without CI occurrence compared to the deterministic ResNet and Bayesian-MOPED ensemble.

对流初生贝叶斯深度学习不确定性估计临近预报

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