RIPEX: Observations of a rip current system
MacMahan, Jamie H.
Thornton, Ed B.
Stanton, Timothy P..
MetadataShow full item record
Rip current kinematics and beach morphodynamics were measured for 44 days at Sand City, Monterey Bay, CA using 15 instruments composed of co-located velocity and pressure sensors, acoustic Doppler current profilers, and kinematic GPS surveys. The morphology consisted of a low-tide terrace with incised quasi-periodic rip channels, representative of transverse bars. Offshore (17 m depth) significant wave height and peak period ranged 0.20–3.0 m and 5–20 s. The mean wave direction was consistently near 08 resulting in rip channel morphology, which evolved in response to the changing wave characteristics. An inverse relationship between sediment accreting on the transverse bar and eroding in the rip channel was found. The spatial distribution of sediment is reflected in the background rip current flow field. The mean velocity magnitudes within the rip channel (transverse bars) increased offshore (onshore) with decreasing tidal elevations and increased with increasing sea-swell energy. Eulerian averaged flows were predominantly shoreward on the transverse bars and seaward within the rip channel throughout the experiment, resulting in a persistent cellular circulation, except during low wave energy. The rip current spacing to the rip channel width was less than or equal to two, which suggests that the rip currents are influenced by each other and that no two-dimensional bar return flow should be present. The vertical velocity profile on the bar indicated that the flow was predominantly shoreward. The flow field within the surf zone was depth uniform, except for significant shear occurring near the surface, owing to Stokes drift. The wave-induced transport hypothesis is evaluated.
The article of record as published may be located at http://dx.doi.org/10.1016/j.margeo.2005.03.019
Showing items related by title, author, creator and subject.
MacMahan, J.H.; Scott, T.M.; Brown, J.W.; Brown, J.A.; Austin, M.J. (2009);The macrotidal intermediate-dissipative beaches of the southwest UK display strong seasonality whereby extensive low-tide bar/rip systems form during the spring season. These features reach a state of maximum development ...
Woods, John E. (Monterey, California. Naval Postgraduate School, 2005-09);The interaction between rip channels and cuspate shoreline was examined by analyzing data obtained by the Naval Postgraduate School Imaging System (NAPSIS) during the winter of 2004-2005 in Southern Monterey Bay. Video ...
O'Neill, Andrea C. (Monterey, California. Naval Postgraduate School, 2009-03);As the Navy thrusts operations into global "brown water" environments, a more complete understanding of the phenomena ships and swimmers will encounter in nearshore regions is necessary. Rip currents remain infamous and ...