Skip to main content

Measurements of Reynolds stress in a wind-driven lagoonal estuary


Acoustic Doppler current profilers (ADCPs) have been used to measure Reynolds stresses in tidally dominated environments where wave action was minimal. In this paper, we examine observations from a microtidal estuary where the effects of wind stress and surface waves dominate the velocity variance. Reynolds stress measurements in this setting require a technique for addressing surface gravity wave contamination. We present here a method of reducing the effect of wave motion on Reynolds stresses by subtracting coincident observations along the axis of the ADCP beam. Linear wave theory is used to account for the attenuation of wave orbital velocities with depth. Using this method, Reynolds stress values are brought in line with those predicted by drag laws at the surface and bottom. The apparent Reynolds stress that is removed by the along-axis subtraction is shown to be largely due to the interaction of a slight tilt (1°) in the ADCP and the wave orbital velocity. During periods of stronger wind and waves, there is evidence of enhanced near-surface turbulence and momentum flux, presumably due to breaking waves. During these events, our calculated Reynolds stress magnitudes still appear reasonable, although the directions are suspect. We develop a diagnostic technique that clearly demarcates this region when it occurs. Coincident density profile measurements are used with the ADCP data to compute gradient Richardson numbers throughout the water column. Enhanced Reynolds stresses appear to correspond to Richardson numbers less than one.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15
Fig. 16


  • Agrawal YC, Aubrey DG (1992) Velocity observations above a rippled bed using laser Doppler velocimetry. J Geophys Res 97:20249–20259

    Article  Google Scholar 

  • Brown J, Colling A, Park D, Phillips J, Rothery D, Wright J (1989) Waves, tides and shallow-water processes. Pergamon, Oxford, pp 187

    Google Scholar 

  • Dean RG, Dalrymple RA (2002) Coastal processes with engineering applications. Cambridge University Press, Cambridge

    Google Scholar 

  • Large WG, Pond S (1981) Open ocean momentum flux measurements in moderate to strong winds. J Phys Oceanogr 11:324–336

    Article  Google Scholar 

  • Lu Y, Lueck RG (1999a) Using a broadband ADCP in a tidal channel. Part 1: Mean flow and shear. J Atmos Ocean Technol 16(11):1556–1567

    Article  Google Scholar 

  • Lu Y, Lueck RG (1999b) Using a broadband ADCP in a tidal channel. Part 2: Turbulence. J Atmos Ocean Technol 16(11):1568–1579

    Article  Google Scholar 

  • Luettich RA Jr, McNinch JE, Paerl HW, Peterson CH, Wells JT, Alperin M, Martens CS, Pinckney JL (2000) Neuse River Estuary modeling and monitoring project stage 1: hydrography and circulation, water column nutrients and productivity, sedimentary processes and benthic–pelagic coupling. Report UNC-WRRI-2000-325B, Water Resources Research Institute of the University of North Carolina, Raleigh, NC, p 172

    Google Scholar 

  • Luettich RA Jr, Carr SD, Reynold-Fleming JV, Fulcher CW, McNinch JE (2002) Semi-diurnal seiching in a shallow, micro-tidal lagoonal estuary. Cont Shelf Res 22(11–13):1669–1681

    Article  Google Scholar 

  • Reynolds-Fleming JV, Luettich RA Jr. (2004) Wind-driven lateral variability in the upper Neuse River Estuary. Estuar Coast Shelf Sci 60:395–407

    Article  Google Scholar 

  • Reynolds-Fleming JV, Fleming JG, Luettich RA (2002) Portable, autonomous vertical profiler for estuarine applications. Estuaries 25(1):142–147

    Article  Google Scholar 

  • Rippeth TP, Simpson JH, Williams E (2003) Measurement of the rates of production and dissipation of turbulent kinetic energy in an energetic tidal flow: Red Wharf Bay revisited. J Phys Oceanogr 33:1889–1901

    Article  Google Scholar 

  • Stacey MT, Monismith SG, Burau JR (1999) Measurements of Reynolds stress profiles in unstratified tidal flow. J Geophys Res 104(C5):10933–10949

    Article  Google Scholar 

  • Trowbridge JH (1998) On a technique for measurement of turbulent shear stress in the presence of surface waves. J Atmos Ocean Technol 15:290–298

    Article  Google Scholar 

  • Williams E, Simpson JH (2004) Uncertainties in estimates of Reynolds stress and TKE production rate using the ADCP variance method. J Atmos Ocean Technol 21:347–357

    Article  Google Scholar 

Download references


The authors would like to thank the two anonymous reviewers whose input greatly improved this manuscript. We would like to acknowledge funding for this work from EPA grant R-82867701-0 and NSF grant OCE-0327056 and the SEACOOS program.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Anthony C. Whipple.

Additional information

Responsible editor: Alejandro Souza

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Whipple, A.C., Luettich, R.A. & Seim, H.E. Measurements of Reynolds stress in a wind-driven lagoonal estuary. Ocean Dynamics 56, 169–185 (2006).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


  • Reynolds stress
  • ADCP
  • Wave separation
  • Wind stress
  • Turbulence