Data assimilation with the 2D Navier-Stokes equations: Optimal Gaussian asymptotics for the posterior measure

Fuente: arXiv
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Auteurs principaux: Konen, Dimitri, Nickl, Richard
Format: Preprint
Publié: 2025
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author Konen, Dimitri
Nickl, Richard
author_facet Konen, Dimitri
Nickl, Richard
contents A functional Bernstein - von Mises theorem is proved for posterior measures arising in a data assimilation problem with the two-dimensional Navier-Stokes equation where a Gaussian process prior is assigned to the initial condition of the system. The posterior measure, which provides the update in the space of all trajectories arising from a discrete sample of the (deterministic) dynamics, is shown to be approximated by a Gaussian random vector field arising from the solution to a linear parabolic PDE with Gaussian initial condition. The approximation holds in the strong sense of the supremum norm on the regression functions, showing that predicting future states of Navier-Stokes systems admits root(N)-consistent estimators even for commonly used nonparametric models. Consequences for coverage of credible bands and uncertainty quantification are discussed. A local asymptotic minimax theorem is derived that describes the lower bound for estimating the state of the nonlinear system, which is shown to be attained by the Bayesian data assimilation algorithm.
format Preprint
id arxiv_https___arxiv_org_abs_2507_18279
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Data assimilation with the 2D Navier-Stokes equations: Optimal Gaussian asymptotics for the posterior measure
Konen, Dimitri
Nickl, Richard
Statistics Theory
Analysis of PDEs
Dynamical Systems
Probability
A functional Bernstein - von Mises theorem is proved for posterior measures arising in a data assimilation problem with the two-dimensional Navier-Stokes equation where a Gaussian process prior is assigned to the initial condition of the system. The posterior measure, which provides the update in the space of all trajectories arising from a discrete sample of the (deterministic) dynamics, is shown to be approximated by a Gaussian random vector field arising from the solution to a linear parabolic PDE with Gaussian initial condition. The approximation holds in the strong sense of the supremum norm on the regression functions, showing that predicting future states of Navier-Stokes systems admits root(N)-consistent estimators even for commonly used nonparametric models. Consequences for coverage of credible bands and uncertainty quantification are discussed. A local asymptotic minimax theorem is derived that describes the lower bound for estimating the state of the nonlinear system, which is shown to be attained by the Bayesian data assimilation algorithm.
title Data assimilation with the 2D Navier-Stokes equations: Optimal Gaussian asymptotics for the posterior measure
topic Statistics Theory
Analysis of PDEs
Dynamical Systems
Probability
url https://arxiv.org/abs/2507.18279