Print Email Facebook Twitter Infragravity-wave modulation of short-wave celerity in the surf zone Title Infragravity-wave modulation of short-wave celerity in the surf zone Author Tissier, M. Bonneton, P. Michallet, H. Ruessink, B.G. Faculty Civil Engineering and Geosciences Department Hydraulic Engineering Date 2015-10-20 Abstract The cross-shore evolution of individual wave celerity is investigated using two highresolution laboratory experiments on bichromatic waves. Individual waves are tracked during their onshore propagation and their characteristics, including celerity, are estimated. The intrawave variability in celerity is low in the shoaling zone but increases strongly after breaking. It is maximum when the infragravity-wave height to water depth ratio is the largest, that is to say close to the shoreline. There the observed range of individual wave celerity can be as large as the mean celerity value. This variability can be largely explained by the variations in water depth and velocity induced by the infragravity waves. The differences in celerity are such that they lead to the merging of the waves in the inner surf zone for most of the wave conditions considered. Again, the location at which the first waves start merging strongly correlates with the infragravity-wave height to water depth ratio. The consequences of these findings for celerity-based depth-inversion techniques are finally discussed. Surprisingly, accounting for the infragravity-wave modulation of the velocity field in the celerity estimate does not significantly improve depth estimation in the surf zone. However, it is shown that the occurrence of bore merging decreases significantly the coherence of the avefield in the surf zone. This loss of coherence could hamper celerity estimation from pixel intensity time series and explain, at least partly, the relatively poor performance of depth-inversion techniques in the inner surf zone. To reference this document use: http://resolver.tudelft.nl/uuid:f45e595c-940f-4ebf-bcdd-c22abfa04ed6 Publisher AGU Embargo date 2016-04-20 ISSN 0148-0227 Source Journal Of Geophysical Research: Oceans, 120 (10), 2015 Part of collection Institutional Repository Document type journal article Rights (c) 2015 American Geophysical Union Files PDF 323348.pdf 2.19 MB Close viewer /islandora/object/uuid:f45e595c-940f-4ebf-bcdd-c22abfa04ed6/datastream/OBJ/view