Ocean Dynamics

, 61:1421 | Cite as

Physical and dynamical oceanography of Liverpool Bay

  • Jeffrey A. Polton
  • Matthew Robert Palmer
  • Michael John Howarth
Part of the following topical collections:
  1. Topical Collection on the UK National Oceanography Centre’s Irish Sea Coastal Observatory


The UK National Oceanography Centre has maintained an observatory in Liverpool Bay since August 2002. Over 8 years of observational measurements are used in conjunction with regional ocean modelling data to describe the physical and dynamical oceanography of Liverpool Bay and to validate the regional model, POLCOMS. Tidal dynamics and plume buoyancy govern the fate of the fresh water as it enters the sea, as well as the fate of its sediment, contaminants and nutrient loads. In this context, an overview and summary of Liverpool Bay tidal dynamics are presented. Freshwater forcing statistics are presented showing that on average the bay receives 233 m3 s − 1. Though the region is salinity controlled, river input temperature is shown to significantly modulate the plume buoyancy with a seasonal cycle. Stratification strongly influences the region’s dynamics. Data from long-term moored instrumentation are used to analyse the stratification statistics that are representative of the region. It is shown that for 65% of tidal cycles, the region alternates between being vertically mixed and stratified. Plume dynamics are diagnosed from the model and are presented for the region. The spring–neap modulation of the plume’s westward extent, between 3.5 °W and 4°W, is highlighted. The rapid eastward erosion of the plume during spring tides is identified as a potentially important freshwater mixing mechanism. Novel climatological maps of temperature, salinity and density from the CTD surveys are presented and used to validate numerical simulations. The model is found to be sensitive to the freshwater forcing rates, temperature and salinities. The existing CTD survey grid is shown to not extend sufficiently near the coast to capture the near coastal and vertically mixed component the plume. Instead the survey grid captures the westward spreading, shallow and transient, portion of the plume. This transient plume feature is shown in both the long-term averaged model and observational data as a band of stratified fluid stretching between the mouth of the Mersey towards the Isle of Man. Finally the residual circulation is discussed. Long-term moored ADCP data are favourably compared with model data, showing the general northward flow of surface water and southward trajectory of bottom water.


Liverpool Bay Climatology ROFI Plume dynamics Coastal dynamics Coastal oceanography Shelf sea Model validation 



Wave data were provided by CEFAS as part of the WaveNet project and distributed under the Open Government Licence (http://reference.data.gov.uk/id/open-government-licence). This work was supported by NERC National Oceanography Centre national capability modelling and was partially funded under a NERC New Investigator Award. The authors are grateful for the constructive comments, received through the review processes, which have resulted in an improved manuscript.


  1. Bowden KF (1980) The north west European shelf seas: the sea bed and sea in motion II: Physical and chemical oceanography, and physical resources. In: Banner FT, Collins MB, Massie KS (eds), vol 2, Elsevier, Amsterdam, pp 391–413. doi: 10.1016/j.physletb.2003.10.071
  2. Bowden KF, Sharaf El Din SH (1966) Circulation and mixing processes in the Liverpool Bay area of the Irish Sea. Geophys J R Astron Soc 11:279–292Google Scholar
  3. Bowers DG, Simpson JH (1987) Mean position of tidal fronts in European-shelf seas. Cont Shelf Res 7(1):35–44CrossRefGoogle Scholar
  4. Burchard H (2009) Combined effects of wind, tide, and horizontal density gradients on stratification in estuaries and coastal seas. J Phys Oceanogr 39:2117–2136CrossRefGoogle Scholar
  5. Burchard H, Karsten B (2001) Comparitive analysis of four second-moment turbulence closure models for the oceanic mixed layer. J Phys Oceanogr 31:1943–1968CrossRefGoogle Scholar
  6. Burchard H, Craig PD, Gemmrich JR, van Haren H, Mathieu P-P, Meier HEM, Nimmo Smith WAM, Prandke H, Rippeth TP, Skyllingstad ED, Smyth WD, Welsh DJS, Wijesekera HW (2008) Observational and numerical modeling methods for quantifying coastal ocean turbulence and mixing. Prog Oceanogr 76:399–442CrossRefGoogle Scholar
  7. Burrows R, Walkington IA, Yates NC, Hedges TS, Wolf J, Holt J (2009) The tidal range energy potential of the west coast of the United Kingdom. Appl Ocean Res 31:229–238CrossRefGoogle Scholar
  8. Canuto VM, Howard A, Cheng Y, Dubovikov MS (2001) Ocean turbulence. Part I: one-point closure model—momentum and heat vertical diffusivities. J Phys Oceanogr 31(6):1413–1426CrossRefGoogle Scholar
  9. Fong FW, Heaps NS (1978) Note on quarter wave tidal resonance in the Bristol Channel. Technical report, Bidston Observatory, Birkenhead, Institute of Oceanographic Sciences, 11 pp. I.O.S. Report no. 63 (unpublished)Google Scholar
  10. Heaps NS (1972) Estimation of density currents in the Liverpool Bay area of the Irish Sea. Geophys J R Astron Soc 30:415–432Google Scholar
  11. Holt J, James ID (2001) An s-coordinate model of the northwest European continental shelf. Part I: model description and density structure. J Geophys Res 106(C7):14015–14034CrossRefGoogle Scholar
  12. Holt J, Umlauf L (2008) Modelling the tidal mixing fronts and seasonal stratification of the Northwest European Continental shelf. Cont Shelf Res 28:887–903CrossRefGoogle Scholar
  13. Holt JT, Allen JI, Proctor R, Gilbert F (2005) Error quantification of a high-resolution coupled hydrodynamic-ecosystem coastal-ocean model: part 1 model overview and assessment of the hydrodynamics. J Mar Syst 57:167–188CrossRefGoogle Scholar
  14. Kwong SCM, Davies AM, Flather RA (1997) A three-dimensional model of the principal tides on the European shelf. Prog Oceanogr 39:205–262CrossRefGoogle Scholar
  15. MacCready P, Geyer WR (2010) Advances in estuarine physics. Annu Rev Marine Sci 2:35–58CrossRefGoogle Scholar
  16. Palmer MR (2010) The modification of current ellipses by stratification in the Liverpool Bay ROFI. Ocean Dyn 60:219–226. doi: 10.1007/s10236-009-0246-x CrossRefGoogle Scholar
  17. Pingree RD, Griffiths DK (1978) Tidal fronts on the shelf seas around the British Isles. J Geophys Res 83(C9):4615–4622. doi: 10.1029/JC083iC09p04615 CrossRefGoogle Scholar
  18. Prandle D (1982) The vertical structure of tidal currents. Geophys Astrophys Fluid Dyn 22:29–49CrossRefGoogle Scholar
  19. Prandle D (2004) Saline intrusion in partially mixed estuaries. Estuar Coast Shelf Sci 59:385–397CrossRefGoogle Scholar
  20. Pugh DT (1987) Tides, surges and mean sea-level. Wiley, New YorkGoogle Scholar
  21. Rippeth TP, Fisher NR, Simpson JH (2001) The cycle of turbulent dissipation in the presence of tidal straining. J Phys Oceanogr 31:2458–2471CrossRefGoogle Scholar
  22. Sharples J, Simpson JH (1993) Periodic frontogenesis in a region of freshwater influence. Estuaries 16:74–82CrossRefGoogle Scholar
  23. Sharples J, Simpson JH (1995) Semi-diurnal and longer period stability cycles in the Liverpool Bay region of freshwater influence. Cont Shelf Res 15:295–313CrossRefGoogle Scholar
  24. Simpson JH (1997) Physical processes in the ROFI regime. J Mar Syst 12:3–15CrossRefGoogle Scholar
  25. Simpson JH, Bowers D (1981) Models of stratification and frontal movement in shelf seas. Deep-Sea Res 28A(7):727–738CrossRefGoogle Scholar
  26. Simpson JH, Hunter JR (1974) Fronts in the Irish Sea. Nature 250:404–406CrossRefGoogle Scholar
  27. Simpson JH, Sharples J (1994) Does the earth’s rotation influence the location of the shelf sea fronts? J Geophys Res 99(C2):3315–3319CrossRefGoogle Scholar
  28. Simpson JH, Brown J, Matthews J, Allen G (1990) Tidal straining, density currents, and stirring in the control of estuarine stratification. Estuaries 13:125–132CrossRefGoogle Scholar
  29. Simpson JH, Sharples J, Rippeth TP (1991) A prescriptive model of stratification induced by freshwater runoff. Estuar Coast Shelf Sci 33(1):23–35CrossRefGoogle Scholar
  30. Simpson JH, Burchard H, Fisher NR, Rippeth TP (2002) The semi-diurnal cycle of dissipation in a ROFI: model-measurement comparisons. Cont Shelf Res 22:1615–1628CrossRefGoogle Scholar
  31. Soulsby RL (1983) The bottom boundary layer of shelf seas. In: Johns B (ed) Physical oceanography of coastal and shelf seas. Elsevier, Amsterdam, pp 189–266CrossRefGoogle Scholar
  32. Stacey MT, Burau JR, Monismith SG (2001) Creation of residual flows in a partially stratified estuary. J Geophys Res 106:17013–17037CrossRefGoogle Scholar
  33. The Crown Estate (2010) The UK offshore wind report 2010. http://www.thecrownestate.co.uk/uk_offshore_wind_report_2010.pdf
  34. Verspecht F, Simpson JH, Rippeth TP (2010) Semi-diurnal tidal ellipse variability in a region of freshwater influence. Geophys Res Lett 37(L18602). doi: 10.1029/2010GL044470 Google Scholar
  35. Verspecht F, Rippeth TP, Howarth MJ, Souza AJ, Simpson JH, Burchard H (2009a) Processes impacting on stratification in a region of freshwater influence: application to Liverpool Bay. J Geophys Res 114(C11022). doi: 10.1029/2009JC005475 Google Scholar
  36. Verspecht F, Rippeth TP, Simpson JH, Souza AJ, Burchard H, Howarth MJ (2009b) Residual circulation and stratification in the Liverpool Bay region of freshwater influence. Ocean Dyn 59:765–779. doi: 10.1007/s10236-009-0233-2 CrossRefGoogle Scholar
  37. Visser AW, Souza AJ, Hessner K, Simpson JH (1994) The effect of stratification on tidal current profiles in a region of freshwater influence. Oceanol Acta 17(4):369–381Google Scholar
  38. Walkington I, Burrows R (2009) Modelling tidal stream power potential. Appl Ocean Res 31:239–245CrossRefGoogle Scholar
  39. Wolf J, Brown JM, Howarth MJ (2011) The wave climate of Liverpool Bay—observations and modelling. Ocean Dyn 61(5):639–655. doi: 10.1007/s10236-011-0376-9 CrossRefGoogle Scholar
  40. Yamashita Y, Panton A, Mahaffey C, Jaffé R (2011) Assessing the spatial and temporal variability of dissolved organic matter in Liverpool Bay using excitation–emission matrix fluorescence and parallel factor analysis. Ocean Dyn. doi: 10.1007/s10236-010-0365-4 Google Scholar
  41. Yankovsky AE, Chapman DC (1997) A simple theory for the fate of buoyant coastal discharges. J Phys Oceanogr 27:1386–1401CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Jeffrey A. Polton
    • 1
  • Matthew Robert Palmer
    • 1
  • Michael John Howarth
    • 1
  1. 1.National Oceanography CentreLiverpoolUK

Personalised recommendations