Relationship between high-frequency sediment-level oscillations in the swash zone and inner surf zone wave characteristics under calm wave conditions

Abstract

Swash zone topography rapidly responds to the surf zone waves. Understanding how sandy beaches respond to wave action is critical for beach erosion research, and plays a critical role in the design and maintenance of shore protection structures. The main objectives of this study were to detect the relationship between high-frequency beachface oscillations and surf zone wave characteristics under plunging breakers by using Canonical Correlation Analysis (CCA). The study site is located in Houjiangwan Bay, eastern Guangdong. Topography data were sampled at 6 min intervals. The wave characteristic parameters were calculated by spectrum method. During the field work, the beach showed a reflective state and plunging breakers controlled the surf zone. The beach cusp topography was destructed gradually. The analysis provides 4 canonical correlation processes between the beachface variations and surf zone waves, which explained 95.28% of the overall variation in the data. The result shows wave steepness, the irregularity factor and spectral broadness factor had strong impacts on the topography. The wave steepness was the most important factor for beach profile variations. The results of the present study indicate that data-driven statistical analysis, such as CCA, is useful for analyzing profile response to waves if there is strong correlation between the two variables (beach profiles and wave).

Keywords

• beach morphodynamic
• swash zone
• plunging breaker
• wave steepness
• canonical correlation analysis
• wave characteristic-beach cusp
• houjiangwan beach