When
12:30 – 1:30 p.m., March 5, 2026
Where
Speaker: Barbara Zemskov, The University of Waterloo
Title: Internal tides in small basins: when are they resonant?
Abstract: When they interact with topography in the presence of stratification, astronomically driven barotropic tides lose part of their energy to internal tides that travel within the ocean interior. Many numerical and observational studies on internal tide generation have been focused on either generation at isolated sea floor mounts or generation at the open coast, but not within semi-enclosed basins like bays and straits. Because of their long wavelengths, potentially comparable to horizontal basin scales, internal tides may be resonant with natural basin modes, which could explain previous observations of large amplitude internal tides in some basins. Yet, what is an appropriate basin geometry to elicit a resonant response is poorly understood. Vertical density gradients and tides' interaction with coastal bathymetry are likely to have a significant impact on the generation and dynamics of internal tides. Here, we conduct a series of idealized 3D numerical simulations of semi-enclosed basins that are rotating at the Earth’s frequency and have vertical density gradients and shelf bathymetry along the perimeter of the basin. We force these basins with a periodic tide that travels along the coast to investigate under what physical characteristics of a basin are resonant internal tides generated. Through our parameter sweep, we identify relevant nondimensional parameters that can be used to find characteristics of a basin resonant to a particular frequency. An important result from this study is that, in the presence of basin shelf bathymetry, coupling between basin modes and coastal trapped waves strongly modifies the dynamics of the resonant response.