Modes and emergent time scales of embayed beach dynamics

Published

Journal Article

©2014. American Geophysical Union. All Rights Reserved. In this study, we use a simple numerical model (the Coastline Evolution Model) to explore alongshore transport-driven shoreline dynamics within generalized embayed beaches (neglecting cross-shore effects). Using principal component analysis (PCA), we identify two primary orthogonal modes of shoreline behavior that describe shoreline variation about its unchanging mean position: the rotation mode, which has been previously identified and describes changes in the mean shoreline orientation, and a newly identified breathing mode, which represents changes in shoreline curvature. Wavelet analysis of the PCA mode time series reveals characteristic time scales of these modes (typically years to decades) that emerge within even a statistically constant white-noise wave climate (without changes in external forcing), suggesting that these time scales can arise from internal system dynamics. The time scales of both modes increase linearly with shoreface depth, suggesting that the embayed beach sediment transport dynamics exhibit a diffusive scaling. Key Points PCA identifies two main modes of shoreline behavior in numerical coastline modelRotation mode previously recognized, breathing mode newly identifiedWavelet analysis identifies characteristic internal time scales of modes

Full Text

Duke Authors

Cited Authors

  • Ratliff, KM; Murray, AB

Published Date

  • October 28, 2014

Published In

Volume / Issue

  • 41 / 20

Start / End Page

  • 7270 - 7275

Electronic International Standard Serial Number (EISSN)

  • 1944-8007

International Standard Serial Number (ISSN)

  • 0094-8276

Digital Object Identifier (DOI)

  • 10.1002/2014GL061680

Citation Source

  • Scopus