Boundary Mixing Associated with Tidal and Near-Inertial Internal Waves

Abstract Moorings deployed on the south (August–November 2002) and north (November 2002–June 2003) flanks of the Kaena Ridge, Hawaii, are used to document the flow variability associated with mixing within 200 m from the boundary, deep along the ridge, as part of the Hawaii Ocean Mixing Experiment (HOME). At both sites, strong temperature inversions are detected with vertical scales of ∼100 m. A Thorpe-scale analysis of the overturns yields a time-averaged dissipation near the bottom at the south site (1.2 × 10−8 W kg−1) that is 10 times higher than the north site (1.9 × 10−9 W kg−1), with both higher than the dissipation at similar depths 30 km from the ridge. On the south flank, observed horizontal currents and vertical displacements are dominated by the semidiurnal internal tide. On the north flank, the semidiurnal tide is less energetic than on the south, with a different vertical structure as tidal amplitudes decrease toward the boundary. These differences are attributed to greater separation from th...

[1]  L. Rainville,et al.  Baroclinic Energy Flux at the Hawaiian Ridge: Observations from the R/P FLIP , 2006 .

[2]  M. Levine,et al.  Tidally forced internal waves and overturns observed on a slope: Results from HOME , 2006 .

[3]  M. Gregg,et al.  Persistent Near-Diurnal Internal Waves Observed above a Site of M2 Barotropic-to-Baroclinic Conversion , 2006 .

[4]  M. Merrifield,et al.  Tidal Mixing Events on the Deep Flanks of Kaena Ridge, Hawaii , 2006 .

[5]  Craig M. Lee,et al.  Structure of the Baroclinic Tide Generated at Kaena Ridge, Hawaii , 2006 .

[6]  Craig M. Lee,et al.  An Estimate of Tidal Energy Lost to Turbulence at the Hawaiian Ridge , 2006 .

[7]  Craig M. Lee,et al.  Internal Tides and Turbulence along the 3000-m Isobath of the Hawaiian Ridge , 2006 .

[8]  Carl Wunsch,et al.  VERTICAL MIXING, ENERGY, AND THE GENERAL CIRCULATION OF THE OCEANS , 2004 .

[9]  Craig M. Lee,et al.  From Tides to Mixing Along the Hawaiian Ridge , 2003, Science.

[10]  S. Chiswell.  Deep equatorward propagation of inertial oscillations , 2003 .

[11]  M. Alford,et al.  Redistribution of energy available for ocean mixing by long-range propagation of internal waves , 2003, Nature.

[12]  Stefan Rahmstorf,et al.  Thermohaline circulation: The current climate , 2003, Nature.

[13]  R. Lukas,et al.  Observations of Enhanced Diapycnal Mixing near the Hawaiian Ridge , 2002 .

[14]  P. Holloway,et al.  Model estimates of M2 internal tide energetics at the Hawaiian Ridge , 2002 .

[15]  M. Alford.  Internal Swell Generation: The Spatial Distribution of Energy Flux from the Wind to Mixed Layer Near-Inertial Motions , 2001 .

[16]  C. Garrett.  What is the near-inertial band and why is it different from the rest of the internal wave spectrum? , 2001 .

[17]  J. Gemmrich,et al.  Thermal Fronts Generated by Internal Waves Propagating Obliquely along the Continental Slope , 2001 .

[18]  T. Hibiya,et al.  Spatial and temporal distribution of the wind‐induced internal wave energy available for deep water mixing in the North Pacific , 2000 .

[19]  P. Müller,et al.  Scattering of Internal Waves at Finite Topography in Two Dimensions. Part I: Theory and Case Studies , 2000 .

[20]  W. Munk,et al.  Abyssal recipes II: energetics of tidal and wind mixing , 1998 .

[21]  K. Speer,et al.  Mixing in the Romanche Fracture Zone , 1998 .

[22]  John M. Toole,et al.  Tidally Driven Vorticity, Diurnal Shear, and Turbulence atop Fieberling Seamount , 1997 .

[23]  J. M. Toole,et al.  Spatial Variability of Turbulent Mixing in the Abyssal Ocean , 1997, Science.

[24]  John M. Toole,et al.  Near‐boundary mixing above the flanks of a midlatitude seamount , 1997 .

[25]  G. Egbert.  Tidal data inversion: interpolation and inference , 1997 .

[26]  C. Paulson,et al.  Upper-Ocean Inertial Currents Forced by a Strong Storm. Part I: Data and Comparisons with Linear Theory , 1995 .

[27]  C. Eriksen.  Observations of internal wave reflection off sloping bottoms , 1982 .

[28]  T. Osborn,et al.  Estimates of the Local Rate of Vertical Diffusion from Dissipation Measurements , 1980 .

[29]  L. Armi.  Some evidence for boundary mixing in the deep Ocean , 1978 .

[30]  Stephen Austen Thorpe,et al.  Turbulence and mixing in a Scottish Loch , 1977, Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences.

[31]  K. Leaman,et al.  Vertical energy propagation of inertial waves: A vector spectral analysis of velocity profiles , 1975 .