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Main Authors: Spence, Rylan, Butler, Troy, Dawson, Clint
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2605.11282
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author Spence, Rylan
Butler, Troy
Dawson, Clint
author_facet Spence, Rylan
Butler, Troy
Dawson, Clint
contents Ensemble filtering of chaotic, partially observed systems is often performed with ensembles far smaller than the state dimension resulting in empirical covariances that are low rank. Subsequently, stochastic observation perturbations can degrade both accuracy and probabilistic calibration. We develop a data-consistent perspective on ensemble filtering and introduce the Quantity-of-Interest Principal Component Analysis Ensemble Data Consistent Filter (QPCA-EnDCF), which is a deterministic method that replaces perturbed observations with a spectrally regularized update in observation space. The method whitens forecast--observation residuals, computes an empirical eigendecomposition of the residual covariance, and restricts the correction to a rank-$κ$ subspace before mapping the increment back to state space through an empirical gain. We establish a theoretical framework that separates population and finite-ensemble objects and yields a bias--variance decomposition for the analysis mean. The analysis shows that stochastic EnKF variants incur an irreducible $\mathcal{O}(1/N)$ variance contribution from observation perturbations, whereas QPCA-EnDCF replaces this term with projector-estimation variability that is also $\mathcal{O}(1/N)$ but depends on the retained rank and the cutoff gap through eigenspace stability. Numerical experiments on the Lorenz--96 system in strongly undersampled regimes demonstrate that QPCA-EnDCF substantially improves spread--skill behavior, temporal tracking between spread and error, and rank-histogram reliability relative to sequential and four-dimensional stochastic EnKF. Under the baseline configuration, these calibration gains are accompanied by lower RMSE.
format Preprint
id arxiv_https___arxiv_org_abs_2605_11282
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A Data-Consistent Approach to Ensemble Filtering
Spence, Rylan
Butler, Troy
Dawson, Clint
Statistics Theory
Applications
Ensemble filtering of chaotic, partially observed systems is often performed with ensembles far smaller than the state dimension resulting in empirical covariances that are low rank. Subsequently, stochastic observation perturbations can degrade both accuracy and probabilistic calibration. We develop a data-consistent perspective on ensemble filtering and introduce the Quantity-of-Interest Principal Component Analysis Ensemble Data Consistent Filter (QPCA-EnDCF), which is a deterministic method that replaces perturbed observations with a spectrally regularized update in observation space. The method whitens forecast--observation residuals, computes an empirical eigendecomposition of the residual covariance, and restricts the correction to a rank-$κ$ subspace before mapping the increment back to state space through an empirical gain. We establish a theoretical framework that separates population and finite-ensemble objects and yields a bias--variance decomposition for the analysis mean. The analysis shows that stochastic EnKF variants incur an irreducible $\mathcal{O}(1/N)$ variance contribution from observation perturbations, whereas QPCA-EnDCF replaces this term with projector-estimation variability that is also $\mathcal{O}(1/N)$ but depends on the retained rank and the cutoff gap through eigenspace stability. Numerical experiments on the Lorenz--96 system in strongly undersampled regimes demonstrate that QPCA-EnDCF substantially improves spread--skill behavior, temporal tracking between spread and error, and rank-histogram reliability relative to sequential and four-dimensional stochastic EnKF. Under the baseline configuration, these calibration gains are accompanied by lower RMSE.
title A Data-Consistent Approach to Ensemble Filtering
topic Statistics Theory
Applications
url https://arxiv.org/abs/2605.11282