Collaborative Research: Interactions of internal waves with submesoscale currents in the bottom boundary layer

This research will examine how the waves that appear at the interface between ocean layers (internal waves) interact with near-bottom currents over a sloping bottom. The study will explore how such interactions affect mixing of waters at spatial scales that span the entire ocean. The approach to study the interactions will combine: a) theoretical concepts of how currents can influence the behavior of internal waves near the bottom; b) analyses of measurements already available; and c) computer models in idealized and realistic settings. Special efforts will target the interactions at crucial places of the ocean’s circulation: the Gulf Stream, the East Greenland Current, and the Denmark Strait Overflow. As Broader Impacts, the research will address a topic that affects a range of disciplines, from coastal biogeochemistry to climate. There will be K-12 class visits and contributions to community models. The project will support one postdoctoral scholar, one graduate student, and one undergraduate student from a historically underrepresented group in the geosciences. This study will investigate the interactions between internal waves and submesoscale currents in a sloping bottom boundary layer. It seeks to assess the impacts of such interactions on ocean’s mixing and circulation at basin-wide scales. In particular, the study will explore the interactions between low frequency internal waves (near-inertial and semi-diurnal) and submesoscale currents in the bottom boundary layer. The approach will combine three strategies: a) theoretical considerations of the impact of vertically sheared flow on the dispersion relation for internal waves within the bottom boundary layer, when the Rossby and Richardson numbers are O(1); b) analyses of available observations; and c) state-of-the-art idealized and realistic simulations. Special efforts will target the interactions at crucial pathways of the ocean’s overturning circulation: the Gulf Stream, the East Greenland Current, and the Denmark Strait Overflow. As Broader Impacts, the research will address a topic, internal wave-driven mixing, that affects a range of disciplines, from coastal biogeochemistry to climate. There will be K-12 class visits and contributions to the open-source software Oceananigans and the diagnostic package Oceanostics. The project will support one postdoctoral scholar, one graduate student, and one undergraduate student. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.