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Title (Primary) Using a bias aware EnKF to account for unresolved structure in an unsaturated zone model
Author Erdal, D.; Neuweiler, I.; Wollschl├Ąger, U.;
Journal Water Resources Research
Year 2014
Department MET;
Volume 50
Issue 1
Language englisch;
POF III (all) T31;
Keywords unsaturated zone; EnKF; bias correction; model error; unresolved structure; parameter estimation
UFZ wide themes RU5;
Abstract When predicting flow in the unsaturated zone, any method for modeling the flow will have to define how, and to what level, the subsurface structure is resolved. In this paper, we use the Ensemble Kalman Filter to assimilate local soil water content observations from both a synthetic layered lysimeter and a real field experiment in layered soil in an unsaturated water flow model. We investigate the use of colored noise bias corrections to account for unresolved subsurface layering in a homogeneous model and compare this approach with a fully resolved model. In both models we use a simplified model parameterization in the Ensemble Kalman Filter. The results show that the use of bias corrections can increase the predictive capability of a simplified homogeneous flow model if the bias corrections are applied to the model states. If correct knowledge of the layering structure is available, the fully resolved model performs best. However, if no, or erroneous, layering is used in the model, the use of a homogeneous model with bias corrections can be the better choice for modeling the behavior of the system.
ID 14233
Persistent UFZ Identifier http://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=14233
Erdal, D., Neuweiler, I., Wollschl├Ąger, U. (2014):
Using a bias aware EnKF to account for unresolved structure in an unsaturated zone model
Water Resour. Res. 50 (1), 132 - 147