z-logo
open-access-imgOpen Access
The effects of tides on swash statistics on an intermediate beach
Author(s) -
Guedes R. M. C.,
Bryan K. R.,
Coco G.,
Holman R. A.
Publication year - 2011
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2010jc006660
Subject(s) - swash , geology , shoal , surf zone , infragravity wave , wave height , shore , submarine pipeline , dissipation , accretion (finance) , breaking wave , plage , oceanography , physics , geomorphology , wave propagation , mechanical wave , longitudinal wave , quantum mechanics , astrophysics , thermodynamics
Swash hydrodynamics were investigated on an intermediate beach using runup data obtained from video images. Under mild, near‐constant, offshore wave conditions, the presence of a sandbar and the tidally controlled water depth over its crest determined whether most of the incoming waves broke before reaching the shoreline. This forced a change in the pattern of wave energy dissipation across the surf zone between low and high tide, which was reflected by changes to swash on time scales of a few hours. Significant runup height ( Rs , defined as 4 times the standard deviation of the waterline time series), was found to vary by a factor of 2 between low tide, when most of the waves were breaking over the sandbar ( Rs / Hs ≈ 1.5, where Hs is the offshore significant wave height) and high tide, when the waves were barely breaking ( Rs / Hs ≈ 2.7). The increase in wave energy dissipation during low tide was also associated with changes in swash maxima distribution, a decrease in mean swash period, and increasing energy at infragravity frequencies. Bispectral analysis suggested that this infragravity modulation might have been connected with the presence of secondary waves.

The content you want is available to Zendy users.

Already have an account? Click here to sign in.
Having issues? You can contact us here