Department of Estuarine and Ocean Sciences PhD Proposal Defense by Leticia Fabre De Lima
When: Thursday,
April 4, 2024
2:00 PM
-
3:00 PM
Where: > See description for location
Description: SMAST West 204 and via Zoom.
Abstract: Ocean surface waves are well-known for their crucial role in energy transport, mixing, and their impact on coastal structures. However, the interior of the ocean is also far from at rest. There are internal waves that propagate beneath the sea surface between stratified layers of fluid. These waves span a remarkable range of scales with frequency going from 1 cycle per day to 1 cycle per minute and with horizontal scales as large as 500 kilometers and as small as a few hundred meters.
The broad range of scales exhibited by internal waves, while fascinating, is what also makes it challenging to study them, since the identification of individual plane waves in open ocean data sets is difficult. For certain purposes, a statistical representation of the internal wave field is useful. In a series of historical papers, Garrett and Munk proposed an empirical model (GM spectrum) that describes the oceanic internal wave field, particularly in the deep open ocean. The governing hypothesis of the GM spectrum is that the horizontally-averaged, depth-integrated total energy of the ocean internal wave field is nearly constant across the world oceans. Of course, this universality is not exact, and the deviations from this universality can provide clues to explain the generation, propagation, and dissipation of internal waves.
This project proposes an investigation of the global variability of the internal gravity wave field and its implications for lateral dispersion that is divided into three main goals. First, we propose an alternative formulation of the GM spectrum, which is less approximate and more promising for representing non-hydrostatic internal waves more accurately. Next, we propose the development of a parametric model, which we then fit to a velocity time series available through a global mooring data set in order to investigate observed variability of the internal wave spectrum. Finally, we intend to examine submesoscale lateral dispersion in the ocean interior induced by internal waves.
Abstract: Ocean surface waves are well-known for their crucial role in energy transport, mixing, and their impact on coastal structures. However, the interior of the ocean is also far from at rest. There are internal waves that propagate beneath the sea surface between stratified layers of fluid. These waves span a remarkable range of scales with frequency going from 1 cycle per day to 1 cycle per minute and with horizontal scales as large as 500 kilometers and as small as a few hundred meters.
The broad range of scales exhibited by internal waves, while fascinating, is what also makes it challenging to study them, since the identification of individual plane waves in open ocean data sets is difficult. For certain purposes, a statistical representation of the internal wave field is useful. In a series of historical papers, Garrett and Munk proposed an empirical model (GM spectrum) that describes the oceanic internal wave field, particularly in the deep open ocean. The governing hypothesis of the GM spectrum is that the horizontally-averaged, depth-integrated total energy of the ocean internal wave field is nearly constant across the world oceans. Of course, this universality is not exact, and the deviations from this universality can provide clues to explain the generation, propagation, and dissipation of internal waves.
This project proposes an investigation of the global variability of the internal gravity wave field and its implications for lateral dispersion that is divided into three main goals. First, we propose an alternative formulation of the GM spectrum, which is less approximate and more promising for representing non-hydrostatic internal waves more accurately. Next, we propose the development of a parametric model, which we then fit to a velocity time series available through a global mooring data set in order to investigate observed variability of the internal wave spectrum. Finally, we intend to examine submesoscale lateral dispersion in the ocean interior induced by internal waves.
Contact: > See Description for contact information
Topical Areas: SMAST, Students, Graduate