Download PDFOpen PDF in browserGlobal Sensitivity Analysis for the Gironde Estuary Hydrodynamics with TELEMAC2D8 pages•Published: September 20, 2018AbstractThis paper presents a global sensitivity analysis study applied to a TELEMAC2D nu- merical flood forecast model of Gironde estuary which aims at identifying which input variables should be better described for water levels to be better simulated and forecasted. A variance sensitivity study (ANOVA) was carried out, by calculating Sobol’ indices for all numerical parameters (wind influence coefficient, Strickler friction coefficients for 4 zones) and time-dependent forcings of the model (rivers discharges and maritime boundary con- ditions). It led to the identification of parameters and forcings to which the model is most sensitive for each area of the estuary. Sobol’ indices for 2003 event show a predominance of the influence of the maritime boundary conditions and of Strickler coefficients all along the estuary. A mesh convergence study shows that the results don’t depend on the mesh. Moreover, a special focus on the eigenvalues of the tide signal correlation error function shows no predominance of one mode on the other. These first results are currently used to implement a sequential ensemble Kalman filter improving both the state of the system and the maritime boundary condition and optimizing the friction coefficients over the Gironde estuary.Keyphrases: ensemble kalman filter, gironde estuary, global sensitivity analysis, karhunen loeve decomposition, sobol’ indices, telemac2d, time dependent inputs In: Goffredo La Loggia, Gabriele Freni, Valeria Puleo and Mauro De Marchis (editors). HIC 2018. 13th International Conference on Hydroinformatics, vol 3, pages 1096-1103.
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