Hydrologic evaluation of spatially disaggregated global ensemble rainfall forecasts |
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| Authors: | E Gaborit F Anctil V Fortin G Pelletier |
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| Institution: | 1. Chaire de recherche EDS en prévisions et actions hydrologiques, Department of Civil and Water Engineering, Université Laval, Québec, Qc, Canada;2. Recherche en prévision numérique environnementale, Environment Canada, Montréal, Qc, Canada;3. Department of Civil and Water Engineering, Université Laval, Québec, Qc, Canada |
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| Abstract: | A statistic–stochastic multi‐fractal downscaling technique was evaluated from a hydrologic point of view. Ensemble hydrologic forecasts with a time step of 3 h were performed for original and disaggregated ensemble rainfall forecasts issued by the Canadian Global Ensemble Prediction System in its 2009 operational version. This hydro‐meteorological operational forecasting chain was conducted using the hydrological model SWMM5. The model was implemented on a small 6‐km2 urban catchment located in the Québec City region. The hydrological evaluation was based on the comparison of forecasted flows to the observed ones, calculating several deterministic and probabilistic scores, and drawing rank histograms and reliability diagrams. Disaggregated products led to a better representation of the ensemble members' dispersion. This disaggregation technique represents an interesting way of bridging the gap between the meteorological models' resolution and the high degree of spatial precision sometimes required by hydrological models in their precipitation representation. Copyright © 2013 John Wiley & Sons, Ltd. |
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| Keywords: | stochastic downscaling statistical disaggregation hydro‐meteorological forecasting chain ensemble prediction system operational hydrology |
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