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

Abstract

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 γ B , and the bottom roughness. Several parameters show no sensitivity (threshold depth, eddy viscosity, wave triad parameters, and depth-induced breaking α B ) 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.

Numerical Modeling of Historical Storm Tides and Waves and Their Interactions Along the U.S. East and Gulf Coasts

“…However, in most regions in the coastal ocean, especially under storm conditions, the eddy viscosity has subtle impact on the water level. For example, using a coupled circulation-wave model with a mesh resolution of 5 km, Bastidas et al (2016) found negligible sensitivity of hurricane-induced storm surge to a constant horizontal viscosity between 0 and 100 m 2 s 21 . Our sensitivity analysis also showed that changing the lateral viscosity from 50 to 20 m 2 s 21 causes negligible impacts on the modeled water levels.…”

Numerical Simulation of Large Wave Heights from Super Typhoon Nepartak (2016) in the Eastern Waters of Taiwan

“…Many analytical parametric typhoon models have been developed to construct or reconstruct the wind and air pressure fields of typhoons for simulating storm waves and surges due to their simplicity [34][35][36][37][38][39][40]. The modified Rankine vortex (MRV) typhoon wind model proposed by [37] provides a more accurate wind field [41,42], which is satisfactory for ocean wave and storm surge modeling [4,37,43,44] and was therefore employed in the present study. A shape parameter α is used in the MRV model to adjust the distribution of typhoon wind speed (W) in the radial direction,…”

“…where W max is the maximum wind speed, R max is the radius of maximum wind speed, and α is specified as 0.5 based on the results from [4,40,42]. Atkinson and Holliday [45] suggested an empirical relationship for W max and the central pressure of typhoons (P c ):…”

Model sensitivity for the prediction of extreme sea level events at a wide and fast-flowing estuary: the case of the Río de la Plata

“…The inputs chosen for the analysis of this paper correspond to the main forces in the energy balance of a 2-D barotropic model for a mighty estuary: the energy dissipation by bottom friction, the atmospheric Lateral diffusion (ν) is not considered in the SA because it is known that this parameter does not produce significant changes in 2-D barotropic models (e.g., Simionato et al, 2004b;Bastidas et al, 2016) and this was verified in a preliminary analysis not shown in this paper for the region of interest (Dinapoli, 2016).…”