Modelling cross-shore shoreline change on multiple timescales and their interactions
Schepper, R.; Almar, R.; Bergsma, E.; de Vries, S.; Reniers, A.; Davidson, M.; Splinter, K. (2021). Modelling cross-shore shoreline change on multiple timescales and their interactions. J. Mar. Sci. Eng. 9(6): 582. https://dx.doi.org/10.3390/jmse9060582
In: Journal of Marine Science and Engineering. MDPI: Basel. ISSN 2077-1312; e-ISSN 2077-1312
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| Keyword |
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| Author keywords |
equilibrium shoreline modelling; ShoreFor; cross-shore sediment transport; multiple timescales |
| Authors | | Top |
- Schepper, R.
- Almar, R.
- Bergsma, E.
- de Vries, S.
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- Reniers, A.
- Davidson, M.
- Splinter, K.
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| Abstract |
In this paper, a new approach to model wave-driven, cross-shore shoreline change incorporating multiple timescales is introduced. As a base, we use the equilibrium shoreline prediction model ShoreFor that accounts for a single timescale only. High-resolution shoreline data collected at three distinctly different study sites is used to train the new data-driven model. In addition to the direct forcing approach used in most models, here two additional terms are introduced: a time-upscaling and a time-downscaling term. The upscaling term accounts for the persistent effect of short-term events, such as storms, on the shoreline position. The downscaling term accounts for the effect of long-term shoreline modulations, caused by, for example, climate variability, on shorter event impacts. The multi-timescale model shows improvement compared to the original ShoreFor model (a normalized mean square error improvement during validation of 18 to 59%) at the three contrasted sandy beaches. Moreover, it gains insight in the various timescales (storms to inter-annual) and reveals their interactions that cause shoreline change. We find that extreme forcing events have a persistent shoreline impact and cause 57–73% of the shoreline variability at the three sites. Moreover, long-term shoreline trends affect short-term forcing event impacts and determine 20–27% of the shoreline variability. |
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