Matthieu Andreas de Schipper, Roshanka Ranasinghe, Ad Reniers, Marcel Stive


Nearshore rhythmicity is often initiated in the period just after a storm where the subtidal bar is turned alongshore uniform. The initiation time as well as the length scales of the created rhythmicity varies from one storm period to another. Here we show that the post-storm wave conditions are related to the initiation of the morphological rhythmicity. Narrow-banded and long wave period, both proxies for swell waves, are often found to be present priorto the initiation of rhythmicity. Furthermore, numerical model computations illustrate that swell waves induce significantly larger wave group induced velocities on the bar. These findings imply that the arrival of swell waves can initiate and stimulate the nearshore morphological rhythmicity.


Rhythmicity; Nearshore sandbars; Wave groups

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Brander, R.W, 1999. Field observations on the morphodynamic evolution of a low-energy rip current system, Marine Geology, 157, 199-217 http://dx.doi.org/10.1016/S0025-3227(98)00152-2

Calvete, D., N. Dodd, A. Falques, and S. M. van Leeuwen, 2005. Morphological development of rip channel systems: Normal and near-normal wave incidence, J. Geophys. Res., 110.

Calvete, D., G. Coco, A. Falques and N. Dodd, 2007. (Un)predictability in rip channel systems,Geophys. Res. Lett., 34.

Castelle B., B.G. Ruessink, P. Bonneton, V. Marieu, N. Bruneau, T.D. Price, 2010. Coupling mechanisms in double sandbar systems. Part 1: Patterns and physical explanation. Earth Surface Processes and Landforms.http://dx.doi.org/10.1002/esp.1929

Christensen, E.D., Walstra, D.J., Emerat, N., 2002. Vertical variation of the flow across the surf zone. Coastal Engineering, 45, 169– 198. http://dx.doi.org/10.1016/S0378-3839(02)00033-9

Coco G, A.B. Murray, 2007. Patterns in the sand: from forcing templates to self-organization. Geomorphology, 91, 271–290. http://dx.doi.org/10.1016/j.geomorph.2007.04.023

Holland, K. T., R.A. Holman, T.C. Lippmann, J. Stanley, and N. Plant, 1997. Practical use of video imagery in nearshore oceanographic field studies, IEEE J. Oceanic Eng., 22(1), 81– 92. http://dx.doi.org/10.1109/48.557542

Holman R.A., and J. Stanley, 2007. The history and technical capabilities of Argus, CoastalEngineering, 54, 477–491.http://dx.doi.org/10.1016/j.coastaleng.2007.01.003

Holman R.A., G. Symonds, E.B. Thornton and R. Ranasinghe, 2006. Rip spacing and persistence on an embayed beach, J. Geophys. Res.,111

Holthuijsen, L.H., N. Booij, and T.H.C. Herbers, 1989. A prediction model for stationary short-crested waves in shallow water with ambient currents, Coastal Engineering, 13, 23–54.http://dx.doi.org/10.1016/0378-3839(89)90031-8

Lippmann, T.C. and R.A. Holman, 1989. Quantification of sand bar morphology: a video technique based on wave dissipation, J. Geophys. Res., 94

Long, J. W., and H. T. Özkan-Haller, 2005. Offshore controls on nearshore rip currents, J. Geophys. Res., 110.

Long, J. W., and H. T. Özkan-Haller, 2009. Low-frequency characteristics of wave group–forced vortices, J. Geophys. Res., 114.

MacMahan, J. H., A.J.H.M. Reniers, and E.B. Thornton, 2010. Vortical surf zone velocity fluctuations with 0(10) min period, J. Geophys. Res.,115.

Pape, L., 2008. BLIM toolbox manual. IMAU Report R08-02, Department of Physical Geography, Utrecht University, available from the author upon request.

Ranasinghe, R., G. Symonds, K. Black, and R. A. Holman, 2004. Morphodynamics of intermediate beaches: A video imaging and numerical modeling study, Coastal Engineering, 51, 629– 655.http://dx.doi.org/10.1016/j.coastaleng.2004.07.018

Reniers, A.J.H.M., A.R. Van Dongeren, J.A. Battjes, and E.B. Thornton, 2002. Linear modeling of infragravity waves during Delilah, J. Geophys. Res., 107.

Reniers, A.J.H.M., J.A. Roelvink and E.B. Thornton, 2004. Morphodynamic modeling of an embayed beach under wave group forcing, J. Geophys. Res.,109 Plant, N.G., K.T. Holland, and R.A. Holman, 2006. A dynamical attractor governs beach response to storms, Geophys. Res. Lett., 33.

Roelvink, J. A., 1993. Dissipation in random wave groups incident on a beach, Coastal Engineering, 19, 127– 150.http://dx.doi.org/10.1016/0378-3839(93)90021-Y

Smit, M.W.J., Reniers, A.J.H.M. and M.J.F. Stive, 2010. What determines nearshore sandbar response? (this issue)

Short, A.D. and Trenaman, N.L., 1992. Wave climate of the Sydney region, an energetic and highly variable ocean wave regime. Aust. J. Mar. Freshwater Res. 43, 765–791.http://dx.doi.org/10.1071/MF9920765

Turner, I.L, D. Whyte, B.G. Ruessink and R. Ranasinghe, 2007. Observations of rip spacing, persistence and mobility at a long, straight coastline, Marine Geology, 236, 209–221. http://dx.doi.org/10.1016/j.margeo.2006.10.029

Van Dongeren, A., A. Reniers, J. Battjes, and I. Svendsen, 2003. Numerical modeling of infragravity wave response during DELILAH, J. Geophys. Res., 108.

van Enckevort, I.M.J., Ruessink, B.G., 2001. Effect of hydrodynamics and bathymetry of video estimates of nearshore sand bar position. Journal of Geophysical Research, 106.

van Enckevort, I.M.J., Coco,G., Ruessink, B.G., Suzuki,K., Turner, I.L., Plant, N.G., Holman, R.A., 2004. Field observations of nearshore crescentic sandbars. J. Geophys. Res. 109.

van Vledder, G.P., 1992. Statistics of wave group parameters, Proceedings of 23th International Conference on Coastal Engineering, ASCE, 946-959.

Walstra, D.J.R, J.A. Roelvink and J. Groeneweg, 2000. Calculation of wave-driven currents in a 3D mean flow model. Proceedings of 27th International Conference on Coastal Engineering, ASCE, 1050-1063.

Wright L.D. and A.D. Short, 1984. Morphodynamic variability of surfzone and beaches: a synthesis, Marine Geology, 56, 93–118.http://dx.doi.org/10.1016/0025-3227(84)90008-2

DOI: http://dx.doi.org/10.9753/icce.v32.sediment.47