Heidelberg 2015 – scientific programme

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UP: Fachverband Umweltphysik

UP 15: Bodenkunde und Kryosphäre

UP 15.1: Talk

Friday, March 27, 2015, 10:00–10:15, G/gHS

Soil Hydrology - Simultaneous Estimation of States, Parameters and Boundary Condition with Ensemble Kalman Filter — •Hannes Helmut Bauser, Stefan Jaumann, and Kurt Roth — Institute of Environmental Physics, Heidelberg University, Heidelberg

The Ensemble Kalman Filter (EnKF) is widely used in hydrologic modeling to estimate states and parameters incorporating uncertainties in measurements and all model components. In soil hydrologic modeling, especially the experimental determination of evaporation faces large uncertainties which are relayed to the formulation of the upper boundary condition of the model.

Thus, we expand the EnKF to additionally estimate the upper boundary condition by augmenting the state vector. Lacking a formulation of the forward model of the boundary condition, highly uncertain measurements are implemented as the forward model.

Additionally, the EnKF is applied iteratively allowing the update of the boundary condition to be dampened in case of a strongly non linear relationship of the boundary condition to the measurements.

The proposed new method is successfully tested on a synthetic 1D data set of subsurface water content measurements, imitating a Time Domain Reflectometry (TDR) measurement time-series. The results indicate that this modified EnKF is capable of estimating the upper boundary condition well, as long as a low temporal resolution is sufficient.