Analysis of a Storm-induced Surge Anomaly Under Climate Change with Focus on Sea Level Rise

Abstract:

The impact of sea level rise (SLR) on hurricane storm surge and wind-waves is a non-linear process (Bilskie et al., 2014). Using a high-resolution physics-based numerical model, we examine shelf wave dynamics in general and a shelf anomaly in particular under global climate change scenarios, which include SLR and potential hurricane intensification. To begin it is noted that Hurricane Dennis (2005) produced local storm surge in Apalachee Bay of six to ten feet, but the National Hurricane Center advisory for the region forecast only four to six feet of storm surge. This forecast was based on the relatively weak wind forcing along the west Florida shelf, but the additional storm-induced surge was caused by a remotely forced shelf wave that propagated along the Florida shelf as a topographic Rossby wave (Morey et al.,2006).

These mesoscale processed are studied under climate change scenarios using a state-of-the-art wind-waved hurricane storm surge model (SWAN+ADCIRC) of the northern Gulf of Mexico that encompasses the off-shore regions including the western North Atlantic Ocean, Caribbean Sea, and Gulf of Mexico. The finitie element model penetrates the shoreline along Florida’s “Big Bend” region, the Florida panhandle, Alabama, and the Mississippi coast with high resolution that is sufficient to describe the Gulf Intracoastal Waterway, for example. The large domain and fine mesh resolution included in the model permits the description, and non-linear interaction, of the physics associated with wind-generated waves and hurricane storm surge that produce storm-induced anomalies such as the Rossby wave generated during Hurricane Dennis. Examination of various wave statistics such as significant wave height, mean wave period and direction, and wave radiation stress gradients provide insight into future behavior of storm-induced shelf wave dynamics under global climate change scenarios. This study may impact future statistics and probability distributions for analysis of flood risk by including parameters for shelf wave dynamics.