Investigation of medium-term barred beach behavior using 28-year beach profile data and Rotated Empirical Orthogonal Function analysis

• We investigated barred beach behavior over 28 years using beach profile data.
• We used the first eight empirical orthogonal functions in REOF analysis.
• Inner and outer transition zones were located between foreshore and bar-trough zone.
• Inner transition zone and foreshore covaried over periods shorter than 1 year.

A 28-year beach profile dataset for a stretch of the Hasaki coast in Japan was examined using Rotated Empirical Orthogonal Function (REOF) analysis to investigate the cross-shore variation in the characteristics of beach profile change. The data were obtained weekly, on a micro-tidal wave-dominated intermediate beach, along a survey line extending from the backshore to a water depth of approximately 5 m. REOF analysis using the first eight empirical orthogonal functions led to the study area being divided into five unique zones based on beach profile change patterns, namely the backshore, the foreshore, the inner and outer transition zones and the bar-trough zone. Although these zones were notably distinct from one another, the profiles in foreshore and the shoreward part of the inner transition zone changed in the same way over periods of 6 and 12 months.

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