High-resolution observations of a shear front in a tidal channel

摘要: Abstract The characteristics of a shear front system in tidal channel have been investigated through field study. High-resolution sampling, including three-dimensional measurements current, temperature, salinity, and turbidity, was performed on repeated transects across the frontal zone both with fronts apparent absent. density measured using conductivity/temperature/depth sensors provides proof that is present whether gradient exists. It distinguishable from conventional buoyant fronts, which require strong along-channel gradient. velocities an Acoustic Doppler Current Profiler (ADCP) trapping Global Position System (GPS) drifters indicate evolution has four-stage dynamic process cycle: (1) directional shoal-flood channel-ebb during slack before flood early flood, (2) speed shoal-quick channel-slow after (3) shoal-ebb channel-flood ebb ebb, (4) shoal-slow channel-quick late ebb. Thus, velocity shear, variation current direction either side front, generation mechanism observed system. caused by unequal durations between deep channels shallow shoals discussed herein. Coriolis effect found to be negligible momentum balance analysis. can following alternative mechanisms, according analysis model simulation: differential friction, owing steep bathymetry shoal channel, circulation, coastline bend shoal.