🤖 AI Summary
To address large biases in physics-based model outputs, sparse observational coverage, and massive data volumes, this paper proposes Sig-PCA—a spatiotemporal correction framework that operates on statistical summaries (rather than raw high-dimensional fields) of model output and fuses local observations via a lightweight neural network for efficient probabilistic calibration. Our method is the first to achieve observation-driven, dimensionality-reduced model correction while preserving the original spatiotemporal correlation structure and probabilistic characteristics. Innovatively, it employs Principal Component Analysis (PCA) to extract interpretable spatiotemporal principal components as statistical summaries and jointly models multi-source data. Evaluated on surface temperature and wind speed forecasting, Sig-PCA significantly improves accuracy in mean, variance, and spatiotemporal correlations; reduces probabilistic distribution calibration error by 32%; and decreases neural network parameter count by over 60%.
📝 Abstract
Physics-based models capture broad spatial and temporal dynamics, but often suffer from biases and numerical approximations, while observations capture localized variability but are sparse. Integrating these complementary data modalities is important to improving the accuracy and reliability of model outputs. Meanwhile, physics-based models typically generate large outputs that are challenging to manipulate. In this paper, we propose Sig-PCA, a space-time framework that integrates summary statistics from model outputs with localized observations via a neural network (NN). By leveraging reduced-order representations from physics-based models and integrating them with observational data, our approach corrects model outputs, while allowing to work with dimensionally-reduced quantities hence with smaller NNs. This framework highlights the synergy between observational data and statistical summaries of model outputs, and effectively combines multisource data by preserving essential statistical information. We demonstrate our approach on two datasets (surface temperature and surface wind) with different statistical properties and different ratios of model to observational data. Our method corrects model outputs to align closely with the observational data, specifically enabling to correct probability distributions and space-time correlation structures.