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Analysis of Extreme Events in the Coastal Engineering Environment

Thesis (MSc)--Stellenbosch University, 2015

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Main Author: Stander, Cornel
Other Authors: Diedericks, Gerhardus Petrus Jacobus
Format: Thesis
Language:en_ZA
Published: Stellenbosch : Stellenbosch University 2015
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access_status_str Open Access
author Stander, Cornel
author2 Diedericks, Gerhardus Petrus Jacobus
author_browse Diedericks, Gerhardus Petrus Jacobus
Stander, Cornel
author_facet Diedericks, Gerhardus Petrus Jacobus
Stander, Cornel
author_sort Stander, Cornel
collection Thesis
dc_rights_str_mv Stellenbosch University
description Thesis (MSc)--Stellenbosch University, 2015
format Thesis
id oai:scholar.sun.ac.za:10019.1/97939
institution Stellenbosch University (South Africa)
language en_ZA
last_indexed 2026-06-10T12:44:52.037Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2015
publishDateRange 2015
publishDateSort 2015
publisher Stellenbosch : Stellenbosch University
publisherStr Stellenbosch : Stellenbosch University
record_format dspace
source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/97939 Analysis of Extreme Events in the Coastal Engineering Environment Stander, Cornel Diedericks, Gerhardus Petrus Jacobus Fidder-Woudberg, Sonia Stellenbosch University. Faculty of Science. Department of Mathematical Sciences (Applied Mathematics) Extreme Value Analysis distribution Ocean waves -- Mathematical models Weibull distribution Generalized Pareto distribution Ocean waves -- Measurement Coastal zone management -- South Africa Coastal zone management -- Shore protection UCTD Thesis (MSc)--Stellenbosch University, 2015 ENGLISH ABSTRACT : Coastal zones are subject to storm events and extreme waves with certain return periods. The return period of such events is defined as the average time interceding two independent, consecutive events, similar in nature, i.e., with the same return level. Coastal structures have to be designed to provide sufficient protection against flooding or erosion to a desired return level associated with a particular return period, for example 100 years. Statistical analyses of measured wave data over a time series are used for these estimations. In this study, wave data, measured by a Datawell Waverider buoy, is analysed by means of extreme value analyses. This dataset covers only approximately 18 years. Extreme value theory provides a framework that enables extrapolation in order to estimate the probability of events that are more extreme than any that have already been observed. It can, for example, be used to estimate wave return levels over the next 100 years given only an 18 year history. Different methods for making these estimations are implemented and evaluated. Datasets containing periods where data values are absent (i.e., gaps in a dataset), as well as the effects these missing values have on the estimation of extreme values, are also investigated. Methods for the treatment of gaps are evaluated by using NCEP (National Centre for Environmental Prediction) hindcast data, containing no missing values, and creating incomplete datasets from this data. Estimations are then made based on these incomplete sets. The resulting estimations are compared to the estimations made based on the complete NCEP dataset. Finally, recommendations are made for conducting optimal extreme value analyses, based on this study. AFRIKAANSE OPSOMMING : Kusgebiede is onderhewig aan storms en ekstreme golwe met sekere terugkeer-periodes. Die terugkeer-periode van 'n gebeurtenis word gedefinieer as die gemiddelde tyd tussen twee onafhanklike, opeenvolgende gebeurtenisse, gelyksoortig van aard, met ander woorde, met dieselfde terugkeer-vlak. Kusstrukture moet ontwerp word om genoegsame beskerming teen oorstromings of erosie tot 'n spesifieke terugkeer-vlak, geassosieer met 'n spesi eke terugkeer-periode, byvoorbeeld 'n 100 jaar, te bied. Statistiese analise van gemete golfdata oor 'n tydsreeks word gebruik vir hierdie benaderings. In hierdie studie word golfdata, gemeet deur 'n Datawell Waverider boei, geanaliseer deur middel van ekstreemwaarde analise. Hierdie datastel dek slegs ongeveer 18 jaar. Ekstreemwaarde-teorie bied 'n raamwerk wat ekstrapolasie moontlik maak om die waarskynlikheid van gebeurtenisse te bepaal wat meer ekstreem is as enige gebeurtenisse wat reeds waargeneem is. Dit kan byvoorbeeld gebruik word om golf-terugkeer-vlakke oor die volgende 100 jaar te voorspel, gegewe slegs 'n 18 jaar geskiedenis. Verskillende metodes om hierdie beramings te maak, word ge-implementeer en ge-evalueer. Datastelle met periodes waar datawaardes afwesig is (ook genoem gapings in 'n datastel), asook die uitwerking van hierdie afwesige datawaardes op die beraming van ekstreemwaardes, word ondersoek. Metodes vir die hantering van gapings word ge evalueer deur onvolledige datastelle te skep uit volledige (met ander woorde, sonder enige afwesige waardes) NCEP (National Centre for Environmental Prediction) data. Beramings word dan gemaak gebasseer op die onvolledige datastelle. Hierdie resulterende beramings word vergelyk met die beramings gemaak gebasseer op die volledige NCEP datastel. Uiteindelik word aanbevelings gemaak vir die optimale uitvoering van ekstreemwaarde analise, gebasseer op hierdie studie. 2015-12-14T07:43:18Z 2015-12-14T07:43:18Z 2015-12 Thesis http://hdl.handle.net/10019.1/97939 en_ZA Stellenbosch University viii, 138 pages : illustrations, some colour, maps application/pdf Stellenbosch : Stellenbosch University
spellingShingle Extreme Value Analysis distribution
Ocean waves -- Mathematical models
Weibull distribution
Generalized Pareto distribution
Ocean waves -- Measurement
Coastal zone management -- South Africa
Coastal zone management -- Shore protection
UCTD
Stander, Cornel
Analysis of Extreme Events in the Coastal Engineering Environment
title Analysis of Extreme Events in the Coastal Engineering Environment
title_full Analysis of Extreme Events in the Coastal Engineering Environment
title_fullStr Analysis of Extreme Events in the Coastal Engineering Environment
title_full_unstemmed Analysis of Extreme Events in the Coastal Engineering Environment
title_short Analysis of Extreme Events in the Coastal Engineering Environment
title_sort analysis of extreme events in the coastal engineering environment
topic Extreme Value Analysis distribution
Ocean waves -- Mathematical models
Weibull distribution
Generalized Pareto distribution
Ocean waves -- Measurement
Coastal zone management -- South Africa
Coastal zone management -- Shore protection
UCTD
url http://hdl.handle.net/10019.1/97939
work_keys_str_mv AT standercornel analysisofextremeeventsinthecoastalengineeringenvironment