Université de Neuchâtel

Missing data simulation inside flow rate time-series using multiple-point statistics

Oriani, F ; Borghi, A ; Straubhaar, J ; Mariethoz, Grégoire ; Renard, Philippe

In: Environmental Modelling & Software, 2016, vol. 86, p. 264-276

The direct sampling (DS) multiple-point statistical technique is proposed as a non-parametric missing data simulator for hydrological flow rate time-series. The algorithm makes use of the patterns contained inside a training data set to reproduce the complexity of the missing data. The proposed setup is tested in the reconstruction of a flow rate time-series while considering several missing data...

Université de Neuchâtel

Simulation of rainfall time series from different climatic regions using the direct sampling technique

Oriani, Fabio ; Straubhaar, Julien ; Renard, Philippe ; Mariethoz, Grégoire

In: Hydrology and Earth System Sciences, 2014, vol. 18, p. 3015-3031

The direct sampling technique, belonging to the family of multiple-point statistics, is proposed as a nonparametric alternative to the classical autoregressive and Markovchain-based models for daily rainfall time-series simulation. The algorithm makes use of the patterns contained inside the training image (the past rainfall record) to reproduce the complexity of the signal without inferring its...

Université de Neuchâtel

The Direct Sampling method to perform multiple-point geostatistical simulations

Mariethoz, Grégoire ; Renard, Philippe ; Straubhaar, Julien

In: Water Resources Research, 2010, vol. 46, no. W11536, p. 1-14

Multiple-point geostatistics is a general statistical framework to model spatial fields displaying a wide range of complex structures. In particular, it allows controlling connectivity patterns that have a critical importance for groundwater flow and transport problems. This approach involves considering data events (spatial arrangements of values) derived from a training image (TI). All data...

Université de Neuchâtel

Bayesian inverse problem and optimization with iterative spatial resampling

Mariethoz, Grégoire ; Renard, Philippe ; Caers, Jeff

In: Water Resources Research, 2010, vol. 46, no. W11530, p. 1-17

Measurements are often unable to uniquely characterize the subsurface at a desired modeling resolution. In particular, inverse problems involving the characterization of hydraulic properties are typically ill-posed since they generally present more unknowns than data. In a Bayesian context, solutions to such problems consist of a posterior ensemble of models that fit the data (up to a certain...