Reflection and Bragg Scattering Along Rocky Shores
Abstract
Field observations of shoreline reflection and Bragg scattering for sea and swell waves along varyingrocky shores from Monterey to Santa Cruz, CA, are described in comparison to sandy shores. The estimatesare derived from directional spectra obtained primarily from Global Positioning System (GPS)-based Spotterwave-buoys. Wave reflection and Bragg scattering vary by shoreline type, with sandy shores reflecting up to23% and rocky shores reflecting up to 30% at rocky platforms. However, rocky shores with cliffs reflectedup to 14% and rough rocky shores up to 8%. A new estimator is proposed that accounts for the decrease inreflection for rocky shores associated with increasing shoreline roughness and works well for both rocky andsandy shores (r2=0.45). Bragg scattering was expected along rocky shores due to the large bottom roughnessand scales that coincide with the resonant response for sea and swell waves. However, the absence of Braggscattering is believed to be associated with the non-uniformity of the bottom roughness and moderate bottomprofile slope, which leads to an insufficient number of wave-bottom interactions for development. Thedirectional narrowing with decreasing water depth is similar to sandy shores. The study describes aspects ofsea swell transformation that occurs for rocky shores with observations and theory
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2023
- Accession Number
- AD1212897
Entities
People
- Patrick Collins
Organizations
- Naval Postgraduate School