Ensemble Kalman Filter Inference Of Spatially-Varying Manning'S N Coefficients In The Coastal Ocean
Keywords
ADvanced CIRCulation (ADCIRC) model; Data assimilation; Manning's n coefficients; Singular evolutive interpolated Kalman filter; Uncertainty quantification
Abstract
Ensemble Kalman (EnKF) filtering is an established framework for large scale state estimation problems. EnKFs can also be used for state-parameter estimation, using the so-called “Joint-EnKF” approach. The idea is simply to augment the state vector with the parameters to be estimated and assign invariant dynamics for the time evolution of the parameters. In this contribution, we investigate the efficiency of the Joint-EnKF for estimating spatially-varying Manning's n coefficients used to define the bottom roughness in the Shallow Water Equations (SWEs) of a coastal ocean model. Observation System Simulation Experiments (OSSEs) are conducted using the ADvanced CIRCulation (ADCIRC) model, which solves a modified form of the Shallow Water Equations. A deterministic EnKF, the Singular Evolutive Interpolated Kalman (SEIK) filter, is used to estimate a vector of Manning's n coefficients defined at the model nodal points by assimilating synthetic water elevation data. It is found that with reasonable ensemble size (O(10)), the filter's estimate converges to the reference Manning's field. To enhance performance, we have further reduced the dimension of the parameter search space through a Karhunen-Loéve (KL) expansion. We have also iterated on the filter update step to better account for the nonlinearity of the parameter estimation problem. We study the sensitivity of the system to the ensemble size, localization scale, dimension of retained KL modes, and number of iterations. The performance of the proposed framework in term of estimation accuracy suggests that a well-tuned Joint-EnKF provides a promising robust approach to infer spatially varying seabed roughness parameters in the context of coastal ocean modeling.
Publication Date
7-1-2018
Publication Title
Journal of Hydrology
Volume
562
Number of Pages
664-684
Document Type
Article
Personal Identifier
scopus
DOI Link
https://doi.org/10.1016/j.jhydrol.2018.05.021
Copyright Status
Unknown
Socpus ID
85047644934 (Scopus)
Source API URL
https://api.elsevier.com/content/abstract/scopus_id/85047644934
STARS Citation
Siripatana, Adil; Mayo, Talea; Knio, Omar; Dawson, Clint; and Maître, Olivier Le, "Ensemble Kalman Filter Inference Of Spatially-Varying Manning'S N Coefficients In The Coastal Ocean" (2018). Scopus Export 2015-2019. 10215.
https://stars.library.ucf.edu/scopus2015/10215