Turbulence and mixing at topographic boundaries
Internal tides and currents interacting with sub-surface topography such as continental slopes, islands and seamounts give rise to turbulent processes. The subsequent mixing of waters of different densities is important for maintaining the global overturning circulation. This thesis investigates the...
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eScholarship, University of California
2024
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ftcdlib:oai:escholarship.org:ark:/13030/qt0gh8c7dc 2024-05-19T07:45:43+00:00 Turbulence and mixing at topographic boundaries Wynne-Cattanach, Bethan Lily Alford, Matthew H 2024-01-01 application/pdf https://escholarship.org/uc/item/0gh8c7dc en eng eScholarship, University of California qt0gh8c7dc https://escholarship.org/uc/item/0gh8c7dc public Physical oceanography Internal Waves Mixing Oceanography Topography Turbulence etd 2024 ftcdlib 2024-04-23T23:49:11Z Internal tides and currents interacting with sub-surface topography such as continental slopes, islands and seamounts give rise to turbulent processes. The subsequent mixing of waters of different densities is important for maintaining the global overturning circulation. This thesis investigates the turbulent processes occurring at two different topographic features; a steep headland in the eastern Pacific and a continental slope canyon in the north-west Atlantic. Tidal currents and mean-flows interacting with headlands and islands give rice to turbulent wakes. In Chapter 1, surveys in the wake of a steep headland in both tidal and mean flow regimes reveal turbulent wakes driven by shear and vorticity in the flow. Recent theoretical literature has suggested that turbulence at steep topographic features may drive upwelling necessary to close the abyssal overturning circulation. In Chapter 2, a novel near-bottom dye release provides the first direct evidence of upwelling within a steep canyon and suggests that current 1-d models of near-bottom processes are insufficient to understand the importance of bottom boundary upwelling processes. In Chapter 3, this work is extended using a suite of moorings which observe convergence and divergence in the along-canyon direction indicative of exchange between the boundary and interior, a process that is not included in 1-d models. Thesis North West Atlantic University of California: eScholarship |
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Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
English |
topic |
Physical oceanography Internal Waves Mixing Oceanography Topography Turbulence |
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Physical oceanography Internal Waves Mixing Oceanography Topography Turbulence Wynne-Cattanach, Bethan Lily Turbulence and mixing at topographic boundaries |
topic_facet |
Physical oceanography Internal Waves Mixing Oceanography Topography Turbulence |
description |
Internal tides and currents interacting with sub-surface topography such as continental slopes, islands and seamounts give rise to turbulent processes. The subsequent mixing of waters of different densities is important for maintaining the global overturning circulation. This thesis investigates the turbulent processes occurring at two different topographic features; a steep headland in the eastern Pacific and a continental slope canyon in the north-west Atlantic. Tidal currents and mean-flows interacting with headlands and islands give rice to turbulent wakes. In Chapter 1, surveys in the wake of a steep headland in both tidal and mean flow regimes reveal turbulent wakes driven by shear and vorticity in the flow. Recent theoretical literature has suggested that turbulence at steep topographic features may drive upwelling necessary to close the abyssal overturning circulation. In Chapter 2, a novel near-bottom dye release provides the first direct evidence of upwelling within a steep canyon and suggests that current 1-d models of near-bottom processes are insufficient to understand the importance of bottom boundary upwelling processes. In Chapter 3, this work is extended using a suite of moorings which observe convergence and divergence in the along-canyon direction indicative of exchange between the boundary and interior, a process that is not included in 1-d models. |
author2 |
Alford, Matthew H |
format |
Thesis |
author |
Wynne-Cattanach, Bethan Lily |
author_facet |
Wynne-Cattanach, Bethan Lily |
author_sort |
Wynne-Cattanach, Bethan Lily |
title |
Turbulence and mixing at topographic boundaries |
title_short |
Turbulence and mixing at topographic boundaries |
title_full |
Turbulence and mixing at topographic boundaries |
title_fullStr |
Turbulence and mixing at topographic boundaries |
title_full_unstemmed |
Turbulence and mixing at topographic boundaries |
title_sort |
turbulence and mixing at topographic boundaries |
publisher |
eScholarship, University of California |
publishDate |
2024 |
url |
https://escholarship.org/uc/item/0gh8c7dc |
genre |
North West Atlantic |
genre_facet |
North West Atlantic |
op_relation |
qt0gh8c7dc https://escholarship.org/uc/item/0gh8c7dc |
op_rights |
public |
_version_ |
1799485823395037184 |