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Dynamic averaging of rainfall-runoff model simulations within non stationary climate conditions Nicolas Le Moine & Ludovic Oudin Univ. Paris 6. Coping with non stationary behaviors: models with more constraints (and robustness) or more freedom (and flexibility)?. Adapting parameterization
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Dynamic averaging of rainfall-runoff model simulations within non stationary climate conditionsNicolas Le Moine & Ludovic OudinUniv. Paris 6 IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions
Coping with non stationary behaviors: models withmore constraints (and robustness) or more freedom (and flexibility)? • Adapting parameterization • Flexibility: Dynamic recalibration with climate analogs (de Vos et al., 2010). • Robustness: Constraining model parameter with multi-objective approach (with e.g. more weights on bias criterion) • Adapting model structure • Flexibility: Multi-model approach • Robustness: Choice of a fixed model structure that is relevant for more arid catchments and/or that is efficient when performing DSST IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions
Reconciling robustness and flexibility • Multi-model / Dynamic averaging / fuzzy comittee : A good idea involving arbitrary choices • Complementary objective functions for calibrating individually the models • A weighting function to average the simulated flows from the models • Is there a way to reduce the number of arbitrary choices? IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions
Data and models • 3 catchments with non-stationnary climate: • Axe Creek • Gilbert • Bani • One daily conceptual model: GR4J IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions
Methodology: Identifying long-term shifts of the hydric state of a catchment through modelling P PE Rainfall-Runoff Model IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions 5
Methodology: Identifying long-term shifts of the hydric state of a catchment through modelling Low frequency signal Mean of the period IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions 6
Methodology: Designing a weighting function IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions 7
Methodology: Designing a weighting function IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions 8
Methodology: Designing a weighting function IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions 9
Methodology: Designing a weighting function Prob. of non exceedance of LowFreq. anomaly IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions 10
Methodology: Designing a weighting function Prob. of non exceedance of LowFreq. anomaly IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions 11
Methodology: Designing a weighting function Prob. of non exceedance of LowFreq. anomaly IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions 12
Methodology: Calibrating bi-polar models IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions
Comparative results for Bias Gilbert River Axe Creek IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions 17
Comparative results for Bias Bani River IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions 18
Comparative results for KGE Axe Creek Gilbert River IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions 19
Comparative results for KGE Bani River IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions 20
Conclusion • A methodology focused on long-term variability • Robustness: each pole has a behavioural parameter set that works by itself • Flexibility: The weights may vary largely on a subperiod but smoothly in time • Need to test other settings • Assessing the methodology on stationary catchments • Effect of time series length • Objective functions IAHS Joint Assembly Gothenburg. Hw15 Testing simulation and forecasting models in non-stationary conditions