Upscaling and Inverse Modeling of Groundwater Flow and Mass ...

Submitted to Hydrol. Earth Syst. Sci..
6
Groundwater Flow Inverse
Modeling in
non-multiGaussian Media:
Performance Assessment of
the Normal-Score Ensemble
Kalman Filter
Abstract
The normal-score ensemble Kalman filter (NS-EnKF) is tested on a synthetic
aquifer characterized by the presence of channels with a bimodal distribution
of its hydraulic conductivities. Fourteen scenarios are analyzed which differ
among them in one or various of the following aspects: the prior random
function model, the boundary conditions of the flow problem, the number of
piezometers used in the assimilation process, or the use of covariance localization
in the implementation of the Kalman filter. The performance of the
NS-EnKF is evaluated through the ensemble mean and variance maps, the
connectivity patterns of the individual conductivity realizations and the degree
of reproduction of the piezometric heads. The results show that (i) the
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