Effects of Wave–Current Interaction on Storm Surge in the Pearl River Estuary: A Case Study of Super Typhoon Mangkhut

Zhifa Luo,Bensheng Huang,Xiaohong Chen,Guangling Huang,Jing Qiu,Chao Tan

doi:10.3389/fmars.2021.692359

Abstract

This study explored the effects of interactions between waves and current on storm surge in the Pearl River Estuary (PRE) using a fully coupled wave–current model. The model was validated based on in situ observations during the traverse of super typhoon Mangkhut. The results indicated that the model could reproduce the storm surge and wave setup processes. Numerical experiments showed that simulations of storm surge are minimally affected by wave setup. The wave setup during super typhoon Mangkhut reached up to 0.23 m and contributed to the total near shore storm surge by up to 8%. The simulations of the coupled model showed a better correlation with observations compared to those of an uncoupled model. The storm surge increased with transport upstream in a tidal-dominated outlet, whereas it decreased in a river-dominated outlet. The storm surge and wave setup increased and decreased, respectively, during spring tide as compared to that during a neap tide. The storm surge increased with increasing runoff in the upper river reaches, whereas there was little change in the tidal-dominated lower river reaches. This research emphasizes the importance of integrating the effects of multiple dynamic factors in the forecasting of storm surge and provides a reference for similar studies in other estuaries with multiple outlets and a complex river network.

Highlights

The interactions between waves, surge, and tide during storm events can be significant in coastal waters due to enhancement by complex hydrodynamic and geomorphic features (Raubenheimer et al, 2001; Malhadas et al, 2009; Tanim and Akter, 2019; He et al, 2020)
This study explored the effects of interactions between waves and current on storm surge in the Pearl River Estuary (PRE) using a fully coupled wave–current model
The mean absolute error of model simulated water level was less than 10 cm, whereas the average relative error (RE) of model simulated flow velocity was less than 10%

Summary

Introduction

The interactions between waves, surge, and tide during storm events can be significant in coastal waters due to enhancement by complex hydrodynamic and geomorphic features (Raubenheimer et al, 2001; Malhadas et al, 2009; Tanim and Akter, 2019; He et al, 2020). There is interaction between tide surge and waves through their effects on the mean water depth/water level and currents. Waves influence water level through wave setup and drive long-shore and cross-shore current through the excess momentum flux induced by waves. This is parameterized as wave radiation stress (Longuet-Higgins and Stewart, 1962, 1964). Significant weight height is strongly influence by time-varying water depth (Bolaños et al, 2014; Yu et al, 2017). Storm surge and wave setup are strongly influenced by tides in shallow water areas (Park and Suh, 2012).

Methods

Results

Discussion

Conclusion