Articles | Volume 16, issue 10
Nat. Hazards Earth Syst. Sci., 16, 2195–2210, 2016
https://doi.org/10.5194/nhess-16-2195-2016
Nat. Hazards Earth Syst. Sci., 16, 2195–2210, 2016
https://doi.org/10.5194/nhess-16-2195-2016

Research article 30 Sep 2016

Research article | 30 Sep 2016

Parameter sensitivity and uncertainty analysis for a storm surge and wave model

Luis A. Bastidas1, James Knighton1,a, and Shaun W. Kline1 Luis A. Bastidas et al.
  • 1ENERCON Services Inc., Pittsburgh, Pennsylvania, USA
  • anow at: Cornell University, Ithaca, New York, USA

Abstract. Development and simulation of synthetic hurricane tracks is a common methodology used to estimate hurricane hazards in the absence of empirical coastal surge and wave observations. Such methods typically rely on numerical models to translate stochastically generated hurricane wind and pressure forcing into coastal surge and wave estimates. The model output uncertainty associated with selection of appropriate model parameters must therefore be addressed. The computational overburden of probabilistic surge hazard estimates is exacerbated by the high dimensionality of numerical surge and wave models. We present a model parameter sensitivity analysis of the Delft3D model for the simulation of hazards posed by Hurricane Bob (1991) utilizing three theoretical wind distributions (NWS23, modified Rankine, and Holland). The sensitive model parameters (of 11 total considered) include wind drag, the depth-induced breaking γB, and the bottom roughness. Several parameters show no sensitivity (threshold depth, eddy viscosity, wave triad parameters, and depth-induced breaking αB) and can therefore be excluded to reduce the computational overburden of probabilistic surge hazard estimates. The sensitive model parameters also demonstrate a large number of interactions between parameters and a nonlinear model response. While model outputs showed sensitivity to several parameters, the ability of these parameters to act as tuning parameters for calibration is somewhat limited as proper model calibration is strongly reliant on accurate wind and pressure forcing data. A comparison of the model performance with forcings from the different wind models is also presented.

Download
Short summary
We present a model parameter sensitivity and uncertainty analysis of the Delft3D model for the simulation of storm hazards. The sensitive model parameters include wind drag, depth-induced breaking, and bottom roughness. Several parameters show no sensitivity and can therefore be excluded to reduce the computational overburden of probabilistic surge hazard estimates. A comparison of the model performance with forcings from three different wind models is also presented.
Altmetrics
Final-revised paper
Preprint