Speaker

Shuwen Tan, Ph.D., Assistant Professor, UConn

Three-Dimensional Shoaling and Breaking of Internal Waves and Future Oceanic Implications in the Internal Surf Zone

Abstract

The internal surf zone, characterized by internal waves confined by water depth, exhibits dynamics analogous to the surf zone of surface gravity waves, where the waves release most of their energy and momentum through turbulent mixing, and the loss of momentum drives currents. This seminar uses idealized numerical modeling to explore the three-dimensional shoaling and breaking of internal waves in the internal surf zone with a curvature/angle of shelf bathymetry and their impacts on wave characteristics, momentum, and energy fluxes, leading to along-shore variations in energy dissipation and current generation. First, I will discuss internal solitary waves interacting with a conical island inspired by Dongsha Atoll in the South China Sea. The interaction of waves with the island results in significant energy dissipation, highest where waves directly impinge on the island and lowest on the opposite side. The curvature of the coastline excites barotropic flow, which is absent for a straight coastline. Next, we examine a straight coastline with internal waves incident at an angle. Preliminary results indicate that this configuration drives an along-shore current within the internal surf zone, analogous to the well-studied along-shore current driven by breaking surface waves. Finally, we will show that internal waves transport cooler, deeper waters into the internal surf zone, reducing warming by up to 2.3°C around the Dongsha Atoll compared to conditions without internal waves. This wave-modulated cooling is projected to continue in a warming ocean, serving as thermal refugia for benthic organisms.