Accession Number : ADA283535


Title :   Tidal Dynamics and Mixing Over Steep Topography


Descriptive Note : Doctoral thesis


Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF OCEANOGRAPHY


Personal Author(s) : Coelho, Emanuel F


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a283535.pdf


Report Date : Jun 1994


Pagination or Media Count : 221


Abstract : Coastal currents and water column stratification frequently are determined by local phenomena that interact to produce complex dynamics. A process study was designed to assess the role of tides over a coastal shelf break as a local source of internal waves spatially-inhomogeneous, baroclinic residual currents, and internal mixing. The temporal evolution of three dimensional stratification and currents were characterized within a 4Kmx4Km box close to the mouth of Monterey Canyon, California. Strong, baroclinic, unidirectional, spatially inhomogeneous jet-like currents were observed with 24 hour periods, together with the occurrence of semidiurnal thermocline oscillations and vertically mixed layers. The linear theory of Baines predicts the existence of significant tidally forced internal waves in the area, with an interfacial mode at the thermocline decoupled from the internal waves propagating in the weaker stratification below. A ray tracing method is developed to study the nonlinear propagation of these tidally forced internal waves by considering wave advection and straining by the topographically controlled barotropic tidal flow while neglecting internal wave-wave interactions. It is found that nonlinear interaction of tidally forced internal waves with the topographically controlled barotropic tidal flow is a mechanism capable of forcing residual currents and internal wave shear instabilities that are capable of creating internal mixed layers similar to those observed at the mouth of Monterey Canyon.


Descriptors :   *TIDAL CURRENTS , COASTAL REGIONS , LAYERS , THESES , RESIDUALS , COASTAL ENGINEERING , AIR WATER INTERACTIONS , RAY TRACING , ADVECTION , CANYONS , JET MIXING FLOW , UNIDIRECTIONAL , OCEAN TIDES , THERMOCLINES , INTERNAL WAVES , STRATIFICATION , OSCILLATION , MIXED LAYER(MARINE) , CALIFORNIA , WAVE PROPAGATION , TOPOGRAPHY , THREE DIMENSIONAL


Subject Categories : Physical and Dynamic Oceanography
      Civil Engineering


Distribution Statement : APPROVED FOR PUBLIC RELEASE