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A new offshore transport mechanism for shoreline‐released tracer induced by transient rip currents and stratification
Author(s) -
Kumar Nirnimesh,
Feddersen Falk
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl072611
Subject(s) - stratification (seeds) , submarine pipeline , shore , oceanography , geology , ocean current , current (fluid) , tracer , surf zone , gravity current , internal wave , botany , dormancy , nuclear physics , biology , seed dormancy , germination , physics
Offshore transport from the shoreline across the inner shelf of early‐stage larvae and pathogens is poorly understood yet is critical for understanding larval fate and dilution of polluted shoreline water. With a novel coupling of a transient rip current (TRC) generating surf zone model and an ocean circulation model, we show that transient rip currents ejected onto a stratified inner shelf induce a new, previously unconsidered offshore transport pathway. For incident waves and stratification typical for Southern California in the fall, this mechanism subducts surf zone‐origin tracers and transports them at least 800 m offshore at 1.2 km/d analogous to subduction at ocean fronts. This mechanism requires both TRCs and stratification. As TRCs are ubiquitous and the inner shelf is often stratified, this mechanism may have an important role in exporting early‐stage larvae, pathogens, or other tracers onto the shelf.