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Potential impacts of global warming on the wave climates of the western and southern coasts of southern Africa
Thesis (MEng)--Stellenbosch University, 2023.
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| Format: | Thesis |
| Language: | en_ZA en_ZA |
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Stellenbosch : Stellenbosch University
2023
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| _version_ | 1867613949743071232 |
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| access_status_str | Open Access |
| author | Marshall, Cole James |
| author2 | Theron, Andre Karl |
| author_browse | Marshall, Cole James Theron, Andre Karl |
| author_facet | Theron, Andre Karl Marshall, Cole James |
| author_sort | Marshall, Cole James |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2023. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/126980 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA en_ZA |
| last_indexed | 2026-06-10T12:44:16.501Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/126980 Potential impacts of global warming on the wave climates of the western and southern coasts of southern Africa Marshall, Cole James Theron, Andre Karl Owen, Robyn Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering. Global warming Ocean waves -- Climate -- Africa, Southern Climatic changes -- Africa, Southern Coastal engineering -- Africa, Southern Thesis (MEng)--Stellenbosch University, 2023. ENGLISH ABSTRACT: Southern Africa is a region which is exposed to a high energy wave climate generated far off shore in the Southern Ocean by very high wind speeds and extra-tropical storms found in the westerly belt in the mid to high-latitudes of the Southern Ocean (Theron et al., 2014). Here, the impacts of global warming on the wave climate of southern Africa are investigated under the IPCC specified warming scenarios of RCP4.5 and RCP8.5. Literature on the climatic drivers of southern African wave climate and the changes already observed in these systems, and literature on global-scale wave projection models is reviewed to establish a foundation for projecting future change in the study area. Using NCEP WaveWatch III and ERA5 reanalysis data from 1979 to 2021, a baseline wave climate at several locations along the coastline of the study region is established, and data analysis on the historical data is performed. Projections for the 2080-2100 end-of-century time slice are made from the projections present in the literature, and short-term projections are made based on trends found in the historic data. In the short-term, there is a projected increase in wave heights and periods at all seasons for both the mean and annual maxima wave parameters, with the winter wave climate showing the most significant increasing trend. There is also a trend of anti-clockwise rotation, especially in the summer months, in mean wave direction that is projected in the short term. In the long-term, this anticlockwise rotation is expected to continue, with up to a 4⁰ rotation expected at some locations by 2100. The long-term projections also show projected increases in winter wave heights and extreme wave heights, however, there are projected decreases for summer wave heights across nearly all locations. 100-year return period wave heights experience the most significant increase of 8% along the southern coast of South Africa. These changes are then contextualised from an engineering standpoint, with calculations performed to show relative changes in wave energy, armour mass requirements, and long-shore sediment transport. These changes are shown to be significant, emphasising the critical nature of addressing and planning for global warming in coastal engineering. AFRIKAANS OPSOMMING: Suider-Afrika is 'n streek wat blootgestel is aan 'n hoë-energie-golfklimaat wat ver van die kus af in die Suidelike Oseaan gegenereer word deur baie hoë windsnelhede en ekstra-tropiese storms, wat in die westelike gordel in die middel tot hoë breedtegrade van die Suidelike Oseaan voorkom (Theron et al., 2014). In hierdie studie word die impak van aardverwarming op die golfklimaat van suidelike Afrika ondersoek onder die IPCC-gespesifiseerde verwarmingscenario's van RCP4.5 en RCP8.5. Literatuur oor die klimaatsdrywers van Suider-Afrikaanse golfklimaat en die veranderinge wat reeds in hierdie stelsels waargeneem is, en literatuur oor globale golfprojeksiemodelle word hersien om 'n grondslag te vestig vir die projektering van toekomstige verandering in die studiegebied. Deur gebruik te maak van NCEP WaveWatch III en ERA5 heranalise data van 1979 tot 2021, word 'n basis golfklimaat op verskeie plekke langs die kuslyn van die studiestreek vasgestel, en data-analise word uitgevoer op die historiese data. Projeksies vir die 2080-2100 einde-van-eeu tydperk word gemaak uit die projeksies wat in die literatuur voorkom, en korttermynprojeksies word gemaak op grond van tendense wat in die historiese data gevind word. Op die korttermyn is daar 'n geprojekteerde toename in golfhoogtes en -periodes tydens alle seisoene vir beide die gemiddelde en jaarlikse maksimum golfparameters, met die wintergolfklimaat wat die mees betekenisvolle stygende neiging toon. Daar is ook 'n neiging van antikloksgewyse rotasie, veral in die somermaande, in gemiddelde golfrigting wat op korttermyn geprojekteer word. Op langtermyn sal hierdie antikloksgewyse rotasie na verwagting voortduur, met tot 'n 4⁰ rotasie wat op sommige plekke teen 2100 verwag word. Die langtermynprojeksies toon ook geprojekteerde toenames in wintergolfhoogtes en uiterste golfhoogtes, maar daar word afnames geprojekteer vir somergolfhoogtes oor byna alle liggings. 100-jaar herhaalperiode golfhoogtes ervaar die mees betekenisvolle toename van 8% langs die suidelike kus van Suid-Afrika. Hierdie veranderinge word dan vanuit 'n ingenieursoogpunt gekontekstualiseer, met berekeninge wat uitgevoer word om relatiewe veranderinge in golfenergie, golfbreker bewapeningseenhede massavereistes en langsstrandse sedimentvervoer aan te toon. Daar word getoon dat hierdie veranderinge betekenisvol is, wat die kritieke aard van aanpassings en beplanning vir aardverwarming in kusingenieurswese beklemtoon. Masters 2023-02-14T21:33:55Z 2023-05-18T06:58:34Z 2023-02-14T21:33:55Z 2023-05-18T06:58:34Z 2023-02 Thesis http://hdl.handle.net/10019.1/126980 en_ZA en_ZA Stellenbosch University xi, 108 pages : illustrations. application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Global warming Ocean waves -- Climate -- Africa, Southern Climatic changes -- Africa, Southern Coastal engineering -- Africa, Southern Marshall, Cole James Potential impacts of global warming on the wave climates of the western and southern coasts of southern Africa |
| title | Potential impacts of global warming on the wave climates of the western and southern coasts of southern Africa |
| title_full | Potential impacts of global warming on the wave climates of the western and southern coasts of southern Africa |
| title_fullStr | Potential impacts of global warming on the wave climates of the western and southern coasts of southern Africa |
| title_full_unstemmed | Potential impacts of global warming on the wave climates of the western and southern coasts of southern Africa |
| title_short | Potential impacts of global warming on the wave climates of the western and southern coasts of southern Africa |
| title_sort | potential impacts of global warming on the wave climates of the western and southern coasts of southern africa |
| topic | Global warming Ocean waves -- Climate -- Africa, Southern Climatic changes -- Africa, Southern Coastal engineering -- Africa, Southern |
| url | http://hdl.handle.net/10019.1/126980 |
| work_keys_str_mv | AT marshallcolejames potentialimpactsofglobalwarmingonthewaveclimatesofthewesternandsoutherncoastsofsouthernafrica |