Design waves for the South African coastline

[摘要] ENGLISH ABSTRACT: Several aspects related to the estimation and selection of design waveconditions were investigated.An analysis program which includes strict quality control routines wasdeveloped for digital Waverider data. All available Waverider data fromdeepsea records were analysed with this program.A remarkable similarity in simultaneously recorded wave heights between CapeTown and Port Elizabeth was found. This similarity was used to compile a nearcontinuous wave record over an eight year period for the Southern Cape coast.The 10537 values of significant wave height (Hmo) which made up the recordfor the Southern Cape were found to give a good visual fit to the Extreme I andLog-normal distributions over the entire range of Hmo values.Design wave heights derived from the Extreme I distribution were found to beinsensitive to assumptions regarding the independence and identicaldistribution of the wave height samples and the method used for parameterestimation.Design wave heights for the coastline between Oranjemund and Port Elizabethwere found to be strongly correlated to the latitude of the recording site.High waves along these coasts are invariably caused by the passage of coldfronts past the southern tip of the continent. Wave heights reduce as thedistance from the west to east route of these cold fronts increase, thus thereason for the abovementioned correlation.No deepwater wave records are available east of Port Elizabeth. Shallow waterrecords indicate that a reduction in wave height can be expected between PortElizabeth and East London.

[发布机构] Stellenbosch University