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A coupled wave, tide and storm surge operational forecasting system for South Africa: validation and physical description
- Source :
- Natural Hazards. 103:1407-1439
- Publication Year :
- 2020
- Publisher :
- Springer Science and Business Media LLC, 2020.
-
Abstract
- Regional storm tidal levels of the South African coastline are investigated by means of a calibrated and validated numerical model. The model was developed utilizing the shallow water hydrodynamic model, Delft3D. This model was coupled (online) with a non-stationary spectral wave model (developed in the Simulating WAves in the Nearshore (SWAN) numerical code). A local, 4.4 km version of the Unified Model was applied as atmospheric forcing for the coupled system. The models presented in this study form part of the operational marine forecasts of the South African Weather Service, Wave and Storm Surge model. The operational protocol and model calibration and validation are presented via statistical correlations with measured water levels at six South African coastal locations. The main calibration parameters and thus physical drivers were winds, atmospheric pressure and waves. The validated numerical model is used to provide an experimental physical description of South African storm surge characteristics, per coastline. The dominant driver of South African storm surge is winds associated with mid-latitude cyclones. Further novelty in the present study is the quantification of the relative contribution of extreme storm wave set-up to the South African storm surge signal. This wave set-up contributes approximately 20% of the total surge signal in the southwest, with winds contributing approximately 55%. The importance of the continental shelves is also elucidated concerning the frictional shoaling effects of the long surge wave propagation.
- Subjects :
- 021110 strategic, defence & security studies
Atmospheric Science
010504 meteorology & atmospheric sciences
Meteorology
Wave propagation
0211 other engineering and technologies
Storm surge
Storm
02 engineering and technology
Unified Model
01 natural sciences
Waves and shallow water
Wave model
Natural hazard
Earth and Planetary Sciences (miscellaneous)
Surge
Geology
0105 earth and related environmental sciences
Water Science and Technology
Subjects
Details
- ISSN :
- 15730840 and 0921030X
- Volume :
- 103
- Database :
- OpenAIRE
- Journal :
- Natural Hazards
- Accession number :
- edsair.doi...........260e8babc5d903033790e87e3a7b9f4d