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Evaluation of two hydro-meteorological ensemble strategies for flash flood forecasting over a catchment of the eastern Pyrenees

Roux, Hélène and Amengual, Arnau and Romero, Romu and Bladé, Ernest and Sanz-Ramos, Marcos Evaluation of two hydro-meteorological ensemble strategies for flash flood forecasting over a catchment of the eastern Pyrenees. (2020) Natural Hazards & Earth System Sciences, 20 (2). 425-450. ISSN 1561-8633

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Official URL: https://doi.org/10.5194/nhess-20-425-2020

Abstract

This study aims at evaluating the performances of flash flood forecasts issued from deterministic and ensemble meteorological prognostic systems. The hydro-meteorological modeling chain includes the Weather Research and Forecasting model (WRF) forcing the rainfall-runoff model MARINE dedicated to flash flood. Two distinct ensemble prediction systems accounting for (i) perturbed initial and lateral boundary conditions of the meteorological state and (ii) mesoscale model physical parameterizations, have been implemented on the Agly catchment of the Eastern Pyrenees with three sub-catchments exhibiting different rainfall regimes. Different evaluations of the performance of the hydro-meteorological strategies have been performed: (i) verification of short-range ensemble prediction systems and corresponding stream flow forecasts, for a better understanding of how forecasts behave, (ii) usual measures derived from a contingency table approach, to test an alert threshold exceedance, and (iii) overall evaluation of the hydro-meteorological chain using the Continuous Rank Probability Score, for a general quantification of the ensemble performances. Results show that the overall discharge forecast is improved by both ensemble strategies with respect to the deterministic forecast. Threshold exceedance detections for flood warning also benefit from large hydro-meteorological ensemble spread. There are no substantial differences between both ensemble strategies on these test cases in terms both of the issuance of flood warnings and the overall performances, suggesting that both sources of external-scale uncertainty are important to take into account.

Item Type:Article
Additional Information:This is an open access article under the CC BY-NC-ND license : https://creativecommons.org/licenses/by-nc-nd/4.0/. Thanks to Natural Hazards & Earth System Sciences. The definitive version of this document is available at: https://www.nat-hazards-earth-syst-sci.net/20/425/2020/
HAL Id:hal-02538339
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
Other partners > Universitat Politècnica de Catalunya - UPC (SPAIN)
Other partners > Universitat de les Illes Balears (SPAIN)
Laboratory name:
Funders:
Eurorégion Pyrénées-Méditerranée - SCHAPI
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Deposited On:25 Mar 2020 08:39

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