TY - JOUR

T1 - Wave-tide interaction modulates nearshore wave height

AU - Lewis, Matt J.

AU - Palmer, Tamsin

AU - Hashemi, Resa

AU - Robins, Peter

AU - Saulter, Andrew

AU - Brown, Jenny

AU - Lewis, Huw

AU - Neill, Simon

N1 - Data Statement - Data in this publication was generated using open sourced software and publicly accessible data, as detailed within the methodology of the publication. Namely, the ocean solver COAWST, ERA-interim and TPXO data. Validation data was from http://wavenet.cefas.co.uk, bodc.ac.uk and http://www.storm-surge.info/ This paper was the result of a collaboration funded by the Welsh Government and Higher Education Funding Council for Wales through the Sêr Cymru National Research Network for Low Carbon, Energy and Environment. SPN and MJL wish to acknowledge the support the Sêr Cymru National Research Network for Low Carbon, Energy and the Environment (NRN-LCEE) and the EPSRC METRIC project EP/ R034664/1. MJL and PR wish to also acknowledge the support from the NERC funded ERIP project BCHEST^ (NE/R009007/1). Finally, all authors wish to thank the organisers of the 15th Waves Workshop, hosted at Liverpool (UK), Bangor University MSc student Laura Ebeler and NERC Research Experience Placement student William Chang .

PY - 2019/3

Y1 - 2019/3

N2 - The combined hazard of large waves occurring at an extreme high water could increase the risk of coastal flooding. Wave-tideinteraction processes are known to modulate the wave climate in regions of strong tidal dynamics, yet this process is typicallyomitted in flood risk assessments. Here, we investigate the role of tidal dynamics in the nearshore wave climate (i.e. water depths> 10 m), with the hypothesis that larger waves occur during high water, when the risk of flooding is greater, because tidaldynamics alter the wave climate propagating into the coast. A dynamically coupled wave-tide modelBCOAWST^was applied tothe Irish Sea for a 2-month period (January–February 2014). High water wave heights were simulated to be 20% larger in someregions, compared with an uncoupled approach, with clear implications for coastal hazards. Three model spatial resolutions wereapplied (1/60°, 1/120°, 1/240°), and, although all models displayed similar validation statistics, differences in the simulated tidalmodulation of wave height were found (up to a 10% difference in high water wave height); therefore, sub-kilometre-scale modelresolution is necessary to capture tidal flow variability and wave-tide interactions around the coast. Additionally, the effects ofpredicted mean sea-level rise were investigated (0.44–2.00 m to reflect likely and extreme sea-level rise by the end of the twenty-first century), showing a 5% increase in high water wave height in some areas. Therefore, some regions may experience a futureincrease in the combined hazard of large waves occurring at an extreme high water.

AB - The combined hazard of large waves occurring at an extreme high water could increase the risk of coastal flooding. Wave-tideinteraction processes are known to modulate the wave climate in regions of strong tidal dynamics, yet this process is typicallyomitted in flood risk assessments. Here, we investigate the role of tidal dynamics in the nearshore wave climate (i.e. water depths> 10 m), with the hypothesis that larger waves occur during high water, when the risk of flooding is greater, because tidaldynamics alter the wave climate propagating into the coast. A dynamically coupled wave-tide modelBCOAWST^was applied tothe Irish Sea for a 2-month period (January–February 2014). High water wave heights were simulated to be 20% larger in someregions, compared with an uncoupled approach, with clear implications for coastal hazards. Three model spatial resolutions wereapplied (1/60°, 1/120°, 1/240°), and, although all models displayed similar validation statistics, differences in the simulated tidalmodulation of wave height were found (up to a 10% difference in high water wave height); therefore, sub-kilometre-scale modelresolution is necessary to capture tidal flow variability and wave-tide interactions around the coast. Additionally, the effects ofpredicted mean sea-level rise were investigated (0.44–2.00 m to reflect likely and extreme sea-level rise by the end of the twenty-first century), showing a 5% increase in high water wave height in some areas. Therefore, some regions may experience a futureincrease in the combined hazard of large waves occurring at an extreme high water.

U2 - 10.1007/s10236-018-01245-z

DO - 10.1007/s10236-018-01245-z

M3 - Article

VL - 69

SP - 367

EP - 384

JO - Ocean Dynamics

JF - Ocean Dynamics

SN - 1616-7341

IS - 3

ER -