Impact of climate change on storm surge for future Typhoon Haiyan-like storms with robust bottom friction parametrization

Accurate modeling of storm surge from tropical cyclones is of major concern for the world's coastal population centers, especially due to recent major disasters such as Typhoon Haiyan as well as the impact of climate change on sea level and storm profiles. Storm surge models typically use the depth-integrated shallow water equations along with bathymetry data and source terms for the momentum flux such as wind stress. Adaptive mesh refinement is often necessary due to large computational domains and the need for fine resolution to track dynamic water levels especially along coastlines. However, as it is still computationally infeasible to capture the microtopography that affect drag and turbulence, these subgrid-scale features are parametrized in depth-averaged models using a bottom friction source term, such as the Manning's n coefficient.

It is important that such parametrizations remain robust across gridsizes and we investigate the effect of bottom friction model selection on inundation results. Here, we model and contrast several scenarios of the 2013 Typhoon Haiyan storm surge using climate projections for the North Pacific Ocean to quantify changes in severity for Haiyan-like storms in a future climate. We simulate these scenarios using GeoClaw, a finite volume solver for the nonlinear shallow water equations with adaptive grid refinement and robust Riemann solvers for wet/dry cells, combined with forcing by prescribed wind and pressure fields.