Ocean Science Journal

, Volume 43, Issue 2, pp 81–90 | Cite as

A study of estuarine flow using the roving adcp data

Article

Abstract

A study of estuarine flows during a neap tide was performed using 13-hour roving acoustic Doppler current profiles (ADCP) and conductivity-temperature-depth (CTD) profiles in the Altamaha River estuary, Georgia, U.S.A. The least-squared harmonic analysis method was used to fit the tidal (M2) component and separate the flow into two components: the tidal and residual (M2-removed) flows. We applied this method to depth-averaged data. Results show that the M2 component demonstrates over 95% of the variability of observation data. As the flow was dominated by the M2 tidal component in a narrow channel, the tidal ellipse distribution was essentially a back-and-forth motion. The amplitude of M2 velocity component increased slightly from the river mouth (0.45 m/sec) to land (0.6 m/sec) and the phase showed fairly constant values in the center of the channel and rapidly decreasing values near the northern and southern shoaling areas. The residual flow and transport calculated from depth-averaged flow shows temporal variability over the tidal time scale. Strong landward flows appeared during slack waters which may be attributed to increased baroclinic forcing when turbulent mixing decreases.

Key words

estuarine flow least-squared harmonic analysis baroclinic forcing turbulent mixing 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Blanton, J.O., G. Lin, and S.A. Elston. 2002. Tidal current asymmetry in shallow estuaries and tidal creeks.Cont. Shelf Res.,22, 1731–1743.CrossRefGoogle Scholar
  2. Di Iorio, D and K. Kang. 2003. Some Physical factors that affect turbulent mixing in Altamaha Sound, Georgia. p. 735–738. In:Proceedings of the 2003 Georgia Water Resources Conferences, April 23-24, 2003, ed. by K. J. Hatcher. The University of Georgia, Athens, GA.Google Scholar
  3. Di Iorio, D. and K. Kang. 2007. Variations of turbulent flow with river discharge in the Altamha River Estuary, Georgia.J. Geophy. Res.,112, C05016.CrossRefGoogle Scholar
  4. Dyer, K.R. 1997. Estuaries: A Physical Introduction. John Wiley and Sons. 197 p.Google Scholar
  5. Dyer, K.R. 1982. Mixing caused by lateral intense seiching within a partially mixed estuary.Estuar. Coast. Shelf Sci.,15, 443–457.CrossRefGoogle Scholar
  6. Foreman, M.G.G. 1979–1996. Manual for Tidal Currents Analysis and Prediction. Institute of Ocean Sciences, Patricia Bay Sidney, British Columbia.Google Scholar
  7. Hansen. D.V. and M. Rattray. 1965. Gravitational circulation in straits and estuaries.J. Mar. Res.,23, 104–122.Google Scholar
  8. Ianniello, J.P. 1977. Tidally induced residual currents in estuaries of constant breadth and depth.J. Mar. Res.,35, 755–786.Google Scholar
  9. Jay, D.A. 1991. Estuarine salt conservation: A lagrangian approach. Estuar.Coast. Shelf Sci.,32, 547–565.CrossRefGoogle Scholar
  10. Jay, D.A. and J.D. Smith. 1990. Circulation, density structure and neap-spring transitions in the Columbia River estuary.Prog. Oceanogr.,25, 81–112.CrossRefGoogle Scholar
  11. Kang, K. and D. Di Iorio. 2006. Depth- and current-induced effects on wave propagation into the Altamaha River Estuary, Georgia.Estuar. Coast. Shelf Sci.,66, 395–408.CrossRefGoogle Scholar
  12. Li, C. and A Valle-Levinson. 1998. Separating baroclinic flow from tidally induced flow in estuaries.J. Geophy. Res.,103, 10405–10417.CrossRefGoogle Scholar
  13. Li, C., A. Valle-Levinson, L.P. Atkinson, and T.C. Royer. 2000. Inference of tidal elevation in shallow water using a vessel-towed acoustic Doppler current profiler.J. Geophy. Res.,105, 26225–26236.CrossRefGoogle Scholar
  14. Li, C., J. Blanton, and C. Chen. 2004. Mapping of tide and tidal flow fields along a tidal channel with vessel-based observation.J. Geophy. Res.,109, C04002.CrossRefGoogle Scholar
  15. Li, C. and J. O’Donnel. 1997. Tidally driven residual circulation in shallow estuarine with lateral depth variation.J. Geophy. Res.,102, 27915–27929.CrossRefGoogle Scholar
  16. Nunes-Vaz, R.A., G.W. Lennon, J.R. de Silva Samarasinghe. 1989. The negative role of turbulence in estuarine mass transport.Estuar. Coast. Shelf Sci.,28, 361–377.CrossRefGoogle Scholar
  17. Pawlowicz, R., B. Beardsley, and S. Lentz. 2002. Classical tidal harmonic analysis including error estimates in MATLAB using T_TIDE.Computers and Geosci.,28, 929–937.CrossRefGoogle Scholar
  18. Pritchard, D.W. 1952. Salinity distribution and circulation in the Chesapeake estuarine system.J. Mar. Res.,11, 106–123.Google Scholar
  19. Pritchard, D.W. 1956. The dynamic structure of a coastal plainestuary.J. Mar. Res.,15, 33–42.Google Scholar
  20. Simpson, J.H. 1997. Physical processes in the ROFI regime.J. Mar. Syst.,12, 3–15.CrossRefGoogle Scholar
  21. Simpson, J., H. Burchard, N.R. Fisher, and T.P. Rippeth. 2002. The semi-diurnal cycle of dissipation in a ROFI: Model-measurement comparisons.Cont. Shelf Res.,22, 1615–1628.CrossRefGoogle Scholar
  22. Simpson, J.H., J. Brown, J. Matthews, and G. Allen. 1990. Tidal straining, density currents, and stirring in the control of estuarine stratification.Estuaries,13, 125–132.CrossRefGoogle Scholar
  23. Stacey, M.T., J.R. Burau, and S.G. Monismith. 2001. Creation of residual flows in a partially stratified estuary.J. Geophy. Res.,106, 17013–17037.CrossRefGoogle Scholar
  24. Valle-Levinson, A., C. Reyes, and R. Sanay. 2003. Effects of bathymetry, friction, and rotation on estuary-ocean exchange.J. Phys. Oceanogr.,33, 2375–2393.CrossRefGoogle Scholar

Copyright information

© Korea Ocean Research and Development Institute(KORDI) and the Korean Society of Oceanography(KSO) 2008

Authors and Affiliations

  1. 1.Typoon and Asian Dust Research LaboratoryNational Institute of Meteorological ResearchKorea
  2. 2.Department of Marine SciencesThe University of GeorgiaAthensUSA

Personalised recommendations