Storm Surge Modeling: Influencing Factors

Abstract

Shallow waters are highly susceptible to coastal storm surges, and thus a comprehensive understanding of physical dynamics is essential to coastal management and nearby communities. Given that physics-based models are more suitable in the highly dynamic and complex coastal and estuarine systems than data-driven methods, this work reviews state-of-the-art storm surge modeling and its influencing factors. Three cases were applied under strong wind conditions and during hurricane events in the nearshore of Lake Michigan and a lagoonal system called the Maryland Coastal Bays (MCBs). For the first case, a pair of wave-current coupled, two-dimensional (2D) models, which included the Advanced Circulation Model (ADCIRC) and the Finite Volume Community Ocean Model (FVCOM), were applied to the nearshore of Lake Michigan under strong wind conditions. Storm surge simulations from both models are sensitive to atmospheric datasets, wind stress calculation methods, and wave radiation stress gradients. Specifically, modeled storm surge is associated with wind speed, its direction, coastal geometry, topography, and wave-induced setup. A three-dimensional (3D), wave-current coupled FVCOM was then applied to the MCBs in the second case during Hurricane Irene (2011). With the inclusion of wave effects (e.g., wave radiation stress), the underestimated storm surge (e.g., 20cm for the 1.01 high water surface elevation mark) was reduced by half (i.e., 10cm or 10%). For the third case, a nested 3D FVCOM based storm surge model was used to simulate the storm surge during the passage of Hurricane Sandy (2012) over the MCBs. It confirms the findings from previous cases that winds are important in storm surge simulations. Further investigations reveal that a nesting model can provide the necessary remote forcing from a large domain and maintain the intricate shoreline and bathymetry of the inner domain in a lagoonal system. In the future, more effort and work on storm surge modeling can be focused on the comparison between 2D and 3D models, using alternative wave-current coupled mechanisms (e.g., vortex-force formalism), and considering the effects of turbulent mixing processes.