Structure of the Black Sea Currents Based on the Results of the LADCP Observations in 2004–2014

The article presents the core results of lowered acoustic Doppler current profiler (LADCP) applied in the Black Sea within 2004–2014. Average features of the vertical structure of currents in the upper 600 m layer are outlined. The linear relation between vertical distribution of kinetic energy isopycnically averaged over the station ensemble and density is established. This relation is traced till the isopycn occurrence depth with density of 17 kg/m (~500 m). The mean current velocity has near constant value about ~ 4 cm/s in lower depth layers (>500 m), which is in a good agreement with autonomic buoys data. The averaged profile of current velocity vertical shears shows two wellseparated maxima in the seasonal and main pycnocline layers. LADCP derived velocity shears are more than ten times exceed the geostrophic current shears. Turbulent vertical mixing coefficient, calculated by the G89 model (Gregg 1989) demonstrates the denominated minimum in the permanent pycnocline (410 m/s) and increases with depth to achieve value 210 m/s at 450 m depth. The profile of current velocity averaged by the ensemble casts in the near bottom boundary layer demonstrates near logarithmic relation.

[1]  A. G. Zatsepin,et al.  Autonomous system for vertical profiling of the marine environment at a moored station , 2013, Oceanology.

[2]  A. Ostrovskii,et al.  Short-term hydrophysical and biological variability over the northeastern Black Sea continental slope as inferred from multiparametric tethered profiler surveys , 2011 .

[3]  Meng Zhou,et al.  Mesoscale distribution and advection of overwintering Calanus finmarchicus off the shelf of northern Norway , 2010 .

[4]  A. Ostrovskii,et al.  Akvazond moored automatic measuring system for vertical profiling of the marine medium , 2008 .

[5]  S. Bacon,et al.  Transports across the 2002 Greenland-Portugal Ovide section and comparison with 1997. , 2007 .

[6]  V. Paka,et al.  Influence of the dynamics of currents on the hydrophysical structure of the waters and the vertical exchange in the active layer of the Black Sea , 2007 .

[7]  H. Svendsen,et al.  Observations of turbulent mixing and hydrography in the marginal ice zone of the Barents Sea , 2007 .

[8]  V. Kushnir.  Bottom boundary layer in the Black Sea: Experimental data, turbulent diffusion, and fluxes , 2007 .

[9]  S. Riser,et al.  Intermediate and deep currents of the Black Sea obtained from autonomous profiling floats , 2006 .

[10]  E. Lemeshko,et al.  Methodical aspects of the application of acoustic Doppler current profilers in the Black Sea , 2006 .

[11]  B. Cisewski,et al.  Upper ocean vertical mixing in the Antarctic Polar Front Zone , 2005 .

[12]  A. Watson,et al.  Turbulent diapycnal mixing in the Nordic Seas , 2004 .

[13]  B. Cisewski,et al.  Absolute transport estimates of total and individual water masses in the northern Greenland Sea derived from hydrographic and acoustic Doppler current profiler measurements , 2003 .

[14]  Thomas B. Sanford,et al.  Reduced mixing from the breaking of internal waves in equatorial waters , 2003, Nature.

[15]  Martin Visbeck,et al.  Deep Velocity Profiling Using Lowered Acoustic Doppler Current Profilers: Bottom Track and Inverse Solutions* , 2002 .

[16]  Eric Kunze,et al.  The Finescale Response of Lowered ADCP Velocity Profiles , 2002 .

[17]  V. Kushnir.  Turbulent diffusion in the near-bottom boundary layer of the Black Sea shelf zone , 1999 .

[18]  A. Stips,et al.  Test measurements with an operational microstructure-turbulence profiler: Detection limit of dissipation rates , 1998, Aquatic Sciences.

[19]  Martin Visbeck,et al.  Deep Velocity Profiling with Self-contained ADCPs , 1993 .

[20]  S. Boguslavsky,et al.  Vertical mesostructure of deep waters in the Black Sea , 1990 .

[21]  E. Firing,et al.  Deep ocean acoustic Doppler current profiling , 1990, Proceedings of the IEEE Fourth Working Conference on Current Measurement.

[22]  M. Gregg,et al.  Scaling turbulent dissipation in the thermocline , 1989 .

[23]  R. Pacanowski,et al.  Parameterization of Vertical Mixing in Numerical Models of Tropical Oceans , 1981 .

[24]  P. Martin,et al.  On the Structure and Dynamics of the Oceanic Bottom Boundary Layer , 1978 .

[25]  G. O. Williams,et al.  Internal wave observations from a midwater float, 2 , 1976 .

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

[27]  Chris Garrett,et al.  Space-Time Scales of Internal Waves' A Progress Report , 1975 .

[28]  John W. Miles,et al.  On the stability of heterogeneous shear flows , 1961, Journal of Fluid Mechanics.

[29]  L. Mee,et al.  Vertical structure of the field of current velocities in the northwest part of the Black Sea based on the LADCP data for May 2004 , 2008 .

[30]  V. Tuzhilkin.  Thermohaline Structure of the Sea , 2007 .

[31]  I. Fer.  Scaling turbulent dissipation in an Arctic fjord , 2006 .

[32]  J. N. Mourn.  Efficiency of mixing in the main thermocline , 1996 .

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