Measuring Turbulent Dissipation Using a Tethered ADCP

AbstractThe structure function method for estimating the dissipation rate of turbulent kinetic energy, previously validated for measurements from seabed fixed mounts, is applied to data from 1.2-MHz acoustic Doppler current profiler (ADCP) instruments operating in pulse–pulse coherent mode and mounted in midwater below a tethered buoy. Movements of the buoy introduce additional relative velocity components, but it is hypothesized that these flow components should not seriously interfere with the turbulence information because (i) horizontal or vertical translation induces the same flow component in all cells of an ADCP beam and (ii) any rotation of the instrument about its center induces flow components that are normal to the beam direction, and thus neither affect the structure function. This hypothesis is tested by comparing a series of dissipation measurements from a moored ADCP with those from a free-falling Vertical Microstructure Profiler (VMP) shear probe deployed from a nearby research vessel. The...

[1]  Patrick M. Holligan,et al.  Phytoplankton distribution and survival in the thermocline , 2001 .

[2]  C. Garrett,et al.  Dynamical Aspects of the Flow Through the Strait of Belle Isle , 1981 .

[3]  J. Simpson,et al.  The role of tidal stirring in controlling the seasonal heat cycle in shelf seas , 1984 .

[4]  S. Elgar,et al.  Spatial Scales of Stress-Carrying Nearshore Turbulence* , 2003 .

[5]  M. J. Howarth,et al.  Reynolds stress observations in continental shelf seas , 2005 .

[6]  Youyu Lu,et al.  Turbulence characteristics in a tidal channel , 2000 .

[7]  M. Inall,et al.  Dissipation of Tidal Energy and Associated Mixing in a Wide Fjord , 2002 .

[8]  A. Elliott,et al.  Internal Waves in the Clyde Sea , 2002 .

[9]  M. Inall,et al.  Measurement of the Rates of Production and Dissipation of Turbulent Kinetic Energy in an Energetic Tidal Flow: Red Wharf Bay Revisited , 2003 .

[10]  Neil K. Ganju,et al.  A Preliminary Evaluation of Near-Transducer Velocities Collected with Low-Blank Acoustic Doppler Current Profiler , 2002 .

[11]  Estimation of TKE dissipation rates in dense bottom plumes using a Pulse Coherent Acoustic Doppler Profiler (PC-ADP) — Structure function approach , 2008 .

[12]  J. Simpson,et al.  A novel technique for measuring the rate of turbulent dissipation in the marine environment , 2006 .

[13]  Christopher R. Sherwood,et al.  Accuracy of a Pulse-Coherent Acoustic Doppler Profiler in a Wave-Dominated Flow , 2004 .

[14]  J. Moum,et al.  Mixing Efficiencies in Turbulent Tidal Fronts: Results from Direct and Indirect Measurements of Density Flux , 1995 .

[15]  Emlyn Jones,et al.  Robust Estimations of Current Velocities with Four-Beam Broadband ADCPs , 2009 .

[16]  A. Gargett,et al.  Local isotropy and the decay of turbulence in a stratified fluid , 1984, Journal of Fluid Mechanics.

[17]  Roger Lhermitte,et al.  Pulse-to-Pulse Coherent Doppler Sonar Signal Processing Techniques , 1984 .

[18]  J. Simpson,et al.  Reynolds Stress and Turbulent Energy Production in a Tidal Channel , 2002 .

[19]  Ramon Cabrera,et al.  Performance of a single-beam pulse-to-pulse coherent Doppler profiler , 1996 .

[20]  Hans Burchard,et al.  Comparing the performance of the Mellor‐Yamada and the κ‐ε two‐equation turbulence models , 1998 .

[21]  S. Monismith,et al.  Measurements of Reynolds stress profiles in unstratified tidal flow , 1999 .

[22]  V. Mohrholz,et al.  Stratification and mixing on sloping boundaries , 2008 .

[23]  J. Simpson,et al.  Uncertainties in Estimates of Reynolds Stress and TKE Production Rate Using the ADCP Variance Method , 2004 .

[24]  A. Lorke.  Boundary mixing in the thermocline of a large lake , 2007 .

[25]  Jürgen Sündermann,et al.  Marine turbulence : theories, observations, and models , 2005 .

[26]  Ann E. Gargett,et al.  Time and space scales of vertical mixing and advection of phytoplankton in the upper ocean , 1983 .

[27]  N Bom,et al.  Decorrelation of intravascular echo signals: potentials for blood velocity estimation. , 1997, The Journal of the Acoustical Society of America.

[28]  J. Simpson,et al.  The Vertical Structure of Turbulent Dissipation in Shelf Seas , 1996 .

[29]  J. Simpson,et al.  Internal seiche modes and bottom boundary‐layer dissipation in a temperate lake from acoustic measurements , 2011 .

[30]  J. MacKinnon,et al.  Shear and Baroclinic Energy Flux on the Summer New England Shelf , 2003 .