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The nearshore dynamics of Matroos Bay : field and theoretical investigations

Bibliography: pages 113-119.

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Bibliographic Details
Main Author: Gunn, Bruce William
Other Authors: Harris, T F W
Format: Thesis
Language:English
Published: Department of Oceanography 2016
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access_status_str Open Access
author Gunn, Bruce William
author2 Harris, T F W
author_browse Gunn, Bruce William
Harris, T F W
author_facet Harris, T F W
Gunn, Bruce William
author_sort Gunn, Bruce William
collection Thesis
description Bibliography: pages 113-119.
format Thesis
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institution University of Cape Town (South Africa)
language eng
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license_str Not specified — see source repository
provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
publishDate 2016
publishDateRange 2016
publishDateSort 2016
publisher Department of Oceanography
publisherStr Department of Oceanography
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source_str UCTD — University of Cape Town Open Access Repository
spelling oai:open.uct.ac.za:11427/17905 The nearshore dynamics of Matroos Bay : field and theoretical investigations Gunn, Bruce William Harris, T F W Oceanography Bibliography: pages 113-119. Field and theoretical investigations were made of the nearshore circulation of Matroos Bay, a small embayment on the south-western coast of Africa. The field study revealed two dominant circulation types, denoted "anticlockwise" and "clockwise". The anticlockwise circulation type was characterized by longshore currents flowing from the back of the bay to the northern headland where a rip current was located. The clockwise circulation type was characterized by longshore currents flowing from the northern headland to the back of the bay where a rip current was situated. Anticlockwise circulation types were primarily found to occur during periods of low waves, the clockwise circulation during periods of high waves. Winds and coastal currents were found not to have a major influence on the circulation within the bay. The theoretical study was based on a model of longshore currents in a semi-circular bay (O'Rourke and Le Blond, 1972). This study showed that a change of the height of the wave could lead to a change in the direction of flow of the longshore current. In agreement with the field study, a low wave height was found to result in an anticlockwise circulation type, a high wave height resulting in a clockwise circulation type. The change from one circulation type to the other depended on the relative strength of two opposing mechanisms. One mechanism arose from the obliquity of the wave approach to the shore. This mechanism generated longshore currents towards the back of the bay and was dominant during high waves. The other mechanism resulted from the non-uniformity of the wave height around the bay and generated longshore currents flowing from the back of the bay. Coastal currents were measured as part of the field study. A fair correlation was-observed between the direction of the coastal current and that of the wind, particularly if the winds were moderate to strong. Temperature and salinity measurements were also made. These properties showed seasonal variations in accord with the principles of upwelling. Surface water was found to have a salinity similar to that found at a depth of 400 to 600 metres in the South Atlantic Ocean. The water was upwelled from a greater depth during the summer than during the winter. Heating of the water was found to be greater in summer than in winter whilst dilution of the water, due to rainfall, was found to be negligible, even during winter. The interchange of water between the bay and the coastal circulation was found to be dependent on the circulation type. 2016-03-17T07:19:13Z 2016-03-17T07:19:13Z 1977 Master Thesis Masters MSc http://hdl.handle.net/11427/17905 eng application/pdf Department of Oceanography Faculty of Science University of Cape Town
spellingShingle Oceanography
Gunn, Bruce William
The nearshore dynamics of Matroos Bay : field and theoretical investigations
thesis_degree_str Master's
title The nearshore dynamics of Matroos Bay : field and theoretical investigations
title_full The nearshore dynamics of Matroos Bay : field and theoretical investigations
title_fullStr The nearshore dynamics of Matroos Bay : field and theoretical investigations
title_full_unstemmed The nearshore dynamics of Matroos Bay : field and theoretical investigations
title_short The nearshore dynamics of Matroos Bay : field and theoretical investigations
title_sort nearshore dynamics of matroos bay field and theoretical investigations
topic Oceanography
url http://hdl.handle.net/11427/17905
work_keys_str_mv AT gunnbrucewilliam thenearshoredynamicsofmatroosbayfieldandtheoreticalinvestigations
AT gunnbrucewilliam nearshoredynamicsofmatroosbayfieldandtheoreticalinvestigations