Modeling surfzone to inner-shelf tracer exchange

TitleModeling surfzone to inner-shelf tracer exchange
Publication TypeJournal Article
Year of Publication2016
AuthorsHally-Rosendahl K., Feddersen F
JournalJournal of Geophysical Research-Oceans
Date Published2016/06
Type of ArticleArticle
ISBN Number2169-9275
Accession NumberWOS:000383467800020
Keywordscurrents; dye; equations; generation; shore; waves; zone

A near-shoreline, continuous dye release at an approximately alongshore-uniform beach (IB09 experiment) is simulated with the wave-resolving Boussinesq model funwaveC. The model generates surfzone eddies and transient rip currents but does not resolve inner-shelf vertical variation or stratification. The funwaveC model reproduces well the observed surfzone and inner-shelf dye observations over roughly 350 m cross-shore and 2 km alongshore. Dye is advected alongshore by wave- and wind-driven currents similarly in the observations and model. Near-shoreline mean dye concentration decays downstream as a power law with similar observed (-0.33) and modeled (-0.38) exponents. Observed and modeled cross-shore mean dye profiles are similar, though modeled inner-shelf dye is somewhat elevated. Observed and modeled alongshore dye transports agree, though with compensating surfzone and inner-shelf errors later in the release. For times <3.5 h (before observed and modeled dye advects beyond the model alongshore domain), observed and modeled dye budgets are similar to each other and close to within 10%, and half the observed and modeled dye is exported to the inner-shelf. Later in the release, surfzone and inner-shelf dye masses are under and overpredicted, respectively. Model-data differences may be due to the model's lack of vertical variation, stratification, or tide. The good overall model-data agreement indicates that nearshore tracer transport and dispersion are realistically simulated over 5 h and 2 km alongshore, and that the model transient rip currents accurately induce cross-shore exchange between the surfzone and inner-shelf.

Short TitleJ Geophys Res-Oceans
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