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dc.contributor.authorBore, Pål Takle
dc.contributor.authorAmdahl, Jørgen
dc.contributor.authorKristiansen, David
dc.date.accessioned2019-09-24T08:51:24Z
dc.date.available2019-09-24T08:51:24Z
dc.date.created2019-09-12T20:44:46Z
dc.date.issued2019-08-15
dc.identifier.citationOcean Engineering. 2019, 186:106055 1-22.nb_NO
dc.identifier.issn0029-8018
dc.identifier.urihttp://hdl.handle.net/11250/2618405
dc.description.abstractKnowledge about extreme ocean currents and their vertical structure is important when designing offshore structures. We propose a method for statistical modelling of extreme vertical current velocity profiles, accounting for factors such as directionality, spatial and temporal dependence, and non-stationarity due to the tide. We first pre-process the data by resolving the observed (vector) currents at each of several water depths into orthogonal major and minor axis components by principal component analysis, and use harmonic analysis to decompose the total (observed) current into the sum of (deterministic) tidal and (stochastic) residual currents. A complete marginal model is then constructed for all residual current components, and the dependence structure between the components is characterized using the conditional extremes model by Heffernan and Tawn (2004). By simulating under this model, estimates of various extremal statistics can be acquired. A simple approach for deriving design current velocity profiles is also proposed. The method is tested using measured current profiles at two coastal locations in Norway, covering a period of 2.5 and 1.5 years. It is demonstrated that the method provides good extrapolations at both locations, and the estimated 10-year design current velocity profiles appear realistic compared to the most extreme velocity profiles observed in the measurements.nb_NO
dc.language.isoengnb_NO
dc.publisherElseviernb_NO
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 Internasjonal*
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/deed.no*
dc.subjectCurrent velocity profilesnb_NO
dc.subjectExtreme current velocitiesnb_NO
dc.subjectMultivariate extreme valuesnb_NO
dc.subjectConditional extremes modelnb_NO
dc.subjectPeaks over thresholdnb_NO
dc.subjectStructural designnb_NO
dc.titleStatistical modelling of extreme ocean current velocity profilesnb_NO
dc.typeJournal articlenb_NO
dc.typePeer reviewednb_NO
dc.description.versionpublishedVersionnb_NO
dc.rights.holder© 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND licensenb_NO
dc.source.pagenumber1-22nb_NO
dc.source.volume186:106055nb_NO
dc.source.journalOcean Engineeringnb_NO
dc.identifier.doi10.1016/j.oceaneng.2019.05.037
dc.identifier.cristin1724230
cristin.unitcode7566,2,0,0
cristin.unitnameSjømatteknologi
cristin.ispublishedtrue
cristin.fulltextoriginal
cristin.qualitycode1


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Attribution-NonCommercial-NoDerivatives 4.0 Internasjonal
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