Ocean and laboratory observations on waves over topography
This thesis addresses the observation, analysis and dynamics of waves as being trapped, generated and focused by sloping topography. ---Shelf waves with diurnal tidal frequency off Greenland--- Tidal analysis has been carried out on current measurements at a “cross-shelf” transect off Greenland at 7...
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Utrecht University
2007
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ftunivutrecht:oai:dspace.library.uu.nl:1874/19156 2023-07-23T04:19:32+02:00 Ocean and laboratory observations on waves over topography Lam, F.P. A. 2007-01-24 image/pdf https://dspace.library.uu.nl/handle/1874/19156 en eng Utrecht University https://dspace.library.uu.nl/handle/1874/19156 info:eu-repo/semantics/OpenAccess Natuur- en Sterrenkunde oceanography fluid dynamics internal waves tides Biscay Greenland Sea continental shelf reflection focusing attractor Dissertation 2007 ftunivutrecht 2023-07-01T23:14:40Z This thesis addresses the observation, analysis and dynamics of waves as being trapped, generated and focused by sloping topography. ---Shelf waves with diurnal tidal frequency off Greenland--- Tidal analysis has been carried out on current measurements at a “cross-shelf” transect off Greenland at 71 N. The diurnal tides manifest themselves mainly as a barotropic continental shelf wave, travelling southward along the shelf slope. This follows from the amplitude distribution of the diurnal tidal components and from the rotation sense of the tidal ellipses at different cross-slope locations, as calculated with simple two-dimensional models. The well organized cross-slope pattern of the velocity amplitudes is absent in observations further north near 75 N. These observations suggest that the local vanishing of the group velocity, which is caused by topography, is of importance for the existence and local amplification of these continental shelf waves with diurnal tidal frequency. ---Tidal and residual currents near the shelf break in Biscay--- Internal-wave energy in continuously stratified fluids propagates in the vertical plane, at an angle set by the wave, buoyancy and Coriolis frequencies. Repeated Acoustic Doppler Current Profiler observations on three transects, crossing the shelf edge, now directly reveal this beam-wise propagation of internal tides in the Bay of Biscay. This confirms previous suggestions based on observations sampled more sparsely in space. The present observation is made by bin-wise harmonic analysis of horizontal currents, leading to the spatial resolution of barotropic and baroclinic semi-diurnal tidal and (time-averaged) residual flows. The observed baroclinic tide compares favourably to that produced by a two-dimensional numerical model. The observations reveal details of the internal tidal beam, including its spatial amplitude distribution, presence of amphidromes and direction of phase propagation. The cross-isobath structure of the along-slope barotropic mean flow shows a localized ... Doctoral or Postdoctoral Thesis Greenland Greenland Sea Utrecht University Repository Greenland |
institution |
Open Polar |
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Utrecht University Repository |
op_collection_id |
ftunivutrecht |
language |
English |
topic |
Natuur- en Sterrenkunde oceanography fluid dynamics internal waves tides Biscay Greenland Sea continental shelf reflection focusing attractor |
spellingShingle |
Natuur- en Sterrenkunde oceanography fluid dynamics internal waves tides Biscay Greenland Sea continental shelf reflection focusing attractor Lam, F.P. A. Ocean and laboratory observations on waves over topography |
topic_facet |
Natuur- en Sterrenkunde oceanography fluid dynamics internal waves tides Biscay Greenland Sea continental shelf reflection focusing attractor |
description |
This thesis addresses the observation, analysis and dynamics of waves as being trapped, generated and focused by sloping topography. ---Shelf waves with diurnal tidal frequency off Greenland--- Tidal analysis has been carried out on current measurements at a “cross-shelf” transect off Greenland at 71 N. The diurnal tides manifest themselves mainly as a barotropic continental shelf wave, travelling southward along the shelf slope. This follows from the amplitude distribution of the diurnal tidal components and from the rotation sense of the tidal ellipses at different cross-slope locations, as calculated with simple two-dimensional models. The well organized cross-slope pattern of the velocity amplitudes is absent in observations further north near 75 N. These observations suggest that the local vanishing of the group velocity, which is caused by topography, is of importance for the existence and local amplification of these continental shelf waves with diurnal tidal frequency. ---Tidal and residual currents near the shelf break in Biscay--- Internal-wave energy in continuously stratified fluids propagates in the vertical plane, at an angle set by the wave, buoyancy and Coriolis frequencies. Repeated Acoustic Doppler Current Profiler observations on three transects, crossing the shelf edge, now directly reveal this beam-wise propagation of internal tides in the Bay of Biscay. This confirms previous suggestions based on observations sampled more sparsely in space. The present observation is made by bin-wise harmonic analysis of horizontal currents, leading to the spatial resolution of barotropic and baroclinic semi-diurnal tidal and (time-averaged) residual flows. The observed baroclinic tide compares favourably to that produced by a two-dimensional numerical model. The observations reveal details of the internal tidal beam, including its spatial amplitude distribution, presence of amphidromes and direction of phase propagation. The cross-isobath structure of the along-slope barotropic mean flow shows a localized ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Lam, F.P. A. |
author_facet |
Lam, F.P. A. |
author_sort |
Lam, F.P. A. |
title |
Ocean and laboratory observations on waves over topography |
title_short |
Ocean and laboratory observations on waves over topography |
title_full |
Ocean and laboratory observations on waves over topography |
title_fullStr |
Ocean and laboratory observations on waves over topography |
title_full_unstemmed |
Ocean and laboratory observations on waves over topography |
title_sort |
ocean and laboratory observations on waves over topography |
publisher |
Utrecht University |
publishDate |
2007 |
url |
https://dspace.library.uu.nl/handle/1874/19156 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Greenland Sea |
genre_facet |
Greenland Greenland Sea |
op_relation |
https://dspace.library.uu.nl/handle/1874/19156 |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1772182713037488128 |