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One-dimensional wave spectrum analysis of wind waves off Cape Town
Wind waves in the vicinity of Cape Town, South Africa, were measured by means of an N.I.O. (England) ship-borne wave recorder, in water depths varying from 12 - 140 metres. One dimensional frequency spectra were computed from the records, by power spectrum analysis, based on the method of Blackman a...
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| Format: | Thesis |
| Language: | English |
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Department of Oceanography
2016
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| _version_ | 1867613266782453760 |
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| access_status_str | Open Access |
| author | Van Ieperen, Maarten Pieter |
| author2 | Harris, T F W |
| author_browse | Harris, T F W Van Ieperen, Maarten Pieter |
| author_facet | Harris, T F W Van Ieperen, Maarten Pieter |
| author_sort | Van Ieperen, Maarten Pieter |
| collection | Thesis |
| description | Wind waves in the vicinity of Cape Town, South Africa, were measured by means of an N.I.O. (England) ship-borne wave recorder, in water depths varying from 12 - 140 metres. One dimensional frequency spectra were computed from the records, by power spectrum analysis, based on the method of Blackman and Tukey, using an I.B.M. 1130 Computer. Assumptions of normality and stationarity were tested. The Gaussian assumption of the waves was found to be acceptable for the waters off Cape Town. At the 5% critical level, using the chi-square test, 3 out of 23 records tested were found to be non-Gaussian. No significant difference between the Gaussian properties of the deep and the shallow stations was found. Tests for stationarity applied to 3 selected records showed 1 record as clearly non-stationary. However, this recording was obtained under fluctuating wind conditions. Comparison of the total variances of the power spectra obtained in shoaling water showed a systematic decrease of variance with depth. Normalised spectra did not show a systematic selective attenuation of the variances with frequency. Factors which might have caused the systematic reduction of the total variances with depth have been examined. The bottom friction factor for this coast was estimated. The mean value of the bottom friction is 0.22. This is higher than found by other workers. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/18125 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:33:25.185Z |
| 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 |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/18125 One-dimensional wave spectrum analysis of wind waves off Cape Town Van Ieperen, Maarten Pieter Harris, T F W Oceanography Wind waves in the vicinity of Cape Town, South Africa, were measured by means of an N.I.O. (England) ship-borne wave recorder, in water depths varying from 12 - 140 metres. One dimensional frequency spectra were computed from the records, by power spectrum analysis, based on the method of Blackman and Tukey, using an I.B.M. 1130 Computer. Assumptions of normality and stationarity were tested. The Gaussian assumption of the waves was found to be acceptable for the waters off Cape Town. At the 5% critical level, using the chi-square test, 3 out of 23 records tested were found to be non-Gaussian. No significant difference between the Gaussian properties of the deep and the shallow stations was found. Tests for stationarity applied to 3 selected records showed 1 record as clearly non-stationary. However, this recording was obtained under fluctuating wind conditions. Comparison of the total variances of the power spectra obtained in shoaling water showed a systematic decrease of variance with depth. Normalised spectra did not show a systematic selective attenuation of the variances with frequency. Factors which might have caused the systematic reduction of the total variances with depth have been examined. The bottom friction factor for this coast was estimated. The mean value of the bottom friction is 0.22. This is higher than found by other workers. 2016-03-21T19:26:15Z 2016-03-21T19:26:15Z 1970 Master Thesis Masters MSc http://hdl.handle.net/11427/18125 eng application/pdf Department of Oceanography Faculty of Science University of Cape Town |
| spellingShingle | Oceanography Van Ieperen, Maarten Pieter One-dimensional wave spectrum analysis of wind waves off Cape Town |
| thesis_degree_str | Master's |
| title | One-dimensional wave spectrum analysis of wind waves off Cape Town |
| title_full | One-dimensional wave spectrum analysis of wind waves off Cape Town |
| title_fullStr | One-dimensional wave spectrum analysis of wind waves off Cape Town |
| title_full_unstemmed | One-dimensional wave spectrum analysis of wind waves off Cape Town |
| title_short | One-dimensional wave spectrum analysis of wind waves off Cape Town |
| title_sort | one dimensional wave spectrum analysis of wind waves off cape town |
| topic | Oceanography |
| url | http://hdl.handle.net/11427/18125 |
| work_keys_str_mv | AT vanieperenmaartenpieter onedimensionalwavespectrumanalysisofwindwavesoffcapetown |