Articles | Volume 9, issue 4
https://doi.org/10.5194/os-9-731-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/os-9-731-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
On the shelf resonances of the English Channel and Irish Sea
D. J. Webb
National Oceanography Centre, Southampton SO14 3ZH, UK
Related authors
David John Webb
EGUsphere, https://doi.org/10.5194/egusphere-2025-3734, https://doi.org/10.5194/egusphere-2025-3734, 2025
This preprint is open for discussion and under review for Ocean Science (OS).
Short summary
Short summary
A modern climate model is used to test the hypothesis that changes observed during El Niños are, in part, forced by changes in the temperature of the North Equatorial Counter Current. This is a warm current that flows eastwards across the Pacific, a few degrees north of the Equator, close to the Inter-Tropical Convection Zone, a major region of deep atmospheric convection. The tests generate a significant El Nino type response in the ocean, giving confidence that the hypothesis is correct.
David John Webb
EGUsphere, https://doi.org/10.5194/egusphere-2024-3560, https://doi.org/10.5194/egusphere-2024-3560, 2024
Preprint withdrawn
Short summary
Short summary
A modern climate model is used to test the hypothesis that changes observed during El Niños are, in part, forced by changes in the temperature of the North Equatorial Counter Current. This is a warm current that flows eastwards across the Pacific, a few degrees north of the Equator, close to the Inter-Tropical Convection Zone, a major region of deep atmospheric convection. The tests generate a significant El Niño type response in the ocean, giving confidence that the hypothesis is correct.
David J. Webb
Ocean Sci., 17, 1585–1604, https://doi.org/10.5194/os-17-1585-2021, https://doi.org/10.5194/os-17-1585-2021, 2021
Short summary
Short summary
Research on strong El Niños has shown that they may be a result of a stronger-than-normal North Equatorial Counter Current, itself triggered by lower-than-normal sea levels that develop early in the year. A numerical model study of the 1981–1982 El Niño shows that the low sea levels are due to local winds in the west Pacific, and this is shown also to be true for the 1997–1998 and 2015–2016 El Niños. As a result, we now have a much better understanding of the mechanism causing strong El Niños.
David J. Webb, Andrew C. Coward, and Helen M. Snaith
Ocean Sci., 16, 565–574, https://doi.org/10.5194/os-16-565-2020, https://doi.org/10.5194/os-16-565-2020, 2020
Short summary
Short summary
In conflict with conventional theory, recent analysis of data from a high-resolution global ocean model showed that the North Equatorial Counter Current was responsible for the unusually warm water which triggered the strong El Niños of 1982–83 and 1997–98. In this paper some of the key physics deduced from the model results are tested against satellite data from the 1997–98 event. The results show that the model closely followed reality during the period, further supporting the new mechanisms.
David John Webb
Ocean Sci., 14, 633–660, https://doi.org/10.5194/os-14-633-2018, https://doi.org/10.5194/os-14-633-2018, 2018
Short summary
Short summary
Results from a high-resolution ocean model show that during the strong El Niños of 1983 and 1998, transport of warm water in the equatorial Pacific was dominated by the North Equatorial Counter Current and not by equatorial Kelvin waves. The results show why the NECC fails to do this in most years and how stronger than normal annual Rossby waves near the Equator can both trigger the El Niño in the western Pacific and help to ensure that the warm water arrives off South America around Christmas.
D. J. Webb
Ocean Sci., 10, 411–426, https://doi.org/10.5194/os-10-411-2014, https://doi.org/10.5194/os-10-411-2014, 2014
David John Webb
EGUsphere, https://doi.org/10.5194/egusphere-2025-3734, https://doi.org/10.5194/egusphere-2025-3734, 2025
This preprint is open for discussion and under review for Ocean Science (OS).
Short summary
Short summary
A modern climate model is used to test the hypothesis that changes observed during El Niños are, in part, forced by changes in the temperature of the North Equatorial Counter Current. This is a warm current that flows eastwards across the Pacific, a few degrees north of the Equator, close to the Inter-Tropical Convection Zone, a major region of deep atmospheric convection. The tests generate a significant El Nino type response in the ocean, giving confidence that the hypothesis is correct.
David John Webb
EGUsphere, https://doi.org/10.5194/egusphere-2024-3560, https://doi.org/10.5194/egusphere-2024-3560, 2024
Preprint withdrawn
Short summary
Short summary
A modern climate model is used to test the hypothesis that changes observed during El Niños are, in part, forced by changes in the temperature of the North Equatorial Counter Current. This is a warm current that flows eastwards across the Pacific, a few degrees north of the Equator, close to the Inter-Tropical Convection Zone, a major region of deep atmospheric convection. The tests generate a significant El Niño type response in the ocean, giving confidence that the hypothesis is correct.
David J. Webb
Ocean Sci., 17, 1585–1604, https://doi.org/10.5194/os-17-1585-2021, https://doi.org/10.5194/os-17-1585-2021, 2021
Short summary
Short summary
Research on strong El Niños has shown that they may be a result of a stronger-than-normal North Equatorial Counter Current, itself triggered by lower-than-normal sea levels that develop early in the year. A numerical model study of the 1981–1982 El Niño shows that the low sea levels are due to local winds in the west Pacific, and this is shown also to be true for the 1997–1998 and 2015–2016 El Niños. As a result, we now have a much better understanding of the mechanism causing strong El Niños.
David J. Webb, Andrew C. Coward, and Helen M. Snaith
Ocean Sci., 16, 565–574, https://doi.org/10.5194/os-16-565-2020, https://doi.org/10.5194/os-16-565-2020, 2020
Short summary
Short summary
In conflict with conventional theory, recent analysis of data from a high-resolution global ocean model showed that the North Equatorial Counter Current was responsible for the unusually warm water which triggered the strong El Niños of 1982–83 and 1997–98. In this paper some of the key physics deduced from the model results are tested against satellite data from the 1997–98 event. The results show that the model closely followed reality during the period, further supporting the new mechanisms.
David John Webb
Ocean Sci., 14, 633–660, https://doi.org/10.5194/os-14-633-2018, https://doi.org/10.5194/os-14-633-2018, 2018
Short summary
Short summary
Results from a high-resolution ocean model show that during the strong El Niños of 1983 and 1998, transport of warm water in the equatorial Pacific was dominated by the North Equatorial Counter Current and not by equatorial Kelvin waves. The results show why the NECC fails to do this in most years and how stronger than normal annual Rossby waves near the Equator can both trigger the El Niño in the western Pacific and help to ensure that the warm water arrives off South America around Christmas.
D. J. Webb
Ocean Sci., 10, 411–426, https://doi.org/10.5194/os-10-411-2014, https://doi.org/10.5194/os-10-411-2014, 2014
Related subject area
Approach: Numerical Models | Depth range: Shelf-sea depth | Geographical range: Shelf Seas | Phenomena: Tides
Effects of sea-level rise on tides and sediment dynamics in a Dutch tidal bay
Non-linear aspects of the tidal dynamics in the Sylt-Rømø Bight, south-eastern North Sea
On the shelf resonances of the Gulf of Carpentaria and the Arafura Sea
Long Jiang, Theo Gerkema, Déborah Idier, Aimée B. A. Slangen, and Karline Soetaert
Ocean Sci., 16, 307–321, https://doi.org/10.5194/os-16-307-2020, https://doi.org/10.5194/os-16-307-2020, 2020
Short summary
Short summary
A model downscaling approach is used to investigate the effects of sea-level rise (SLR) on local tides. Results indicate that SLR induces larger increases in tidal amplitude and stronger nonlinear tidal distortion in the bay compared to the adjacent shelf sea. SLR can also change shallow-water tidal asymmetry and influence the direction and magnitude of bed-load sediment transport. The model downscaling approach is widely applicable for local SLR projections in estuaries and coastal bays.
Vera Fofonova, Alexey Androsov, Lasse Sander, Ivan Kuznetsov, Felipe Amorim, H. Christian Hass, and Karen H. Wiltshire
Ocean Sci., 15, 1761–1782, https://doi.org/10.5194/os-15-1761-2019, https://doi.org/10.5194/os-15-1761-2019, 2019
Short summary
Short summary
This study is dedicated to tidally induced dynamics in the Sylt-Rømø Bight with a focus on the non-linear component. The tidal residual circulation and asymmetric tidal cycles largely define the circulation pattern, transport and accumulation of sediment, and the distribution of bedforms. The newly obtained high-quality bathymetric data supported the use of high-resolution grids (up to 2 m in the intertidal zone) and elaboration of the details of tidal energy transformation in the domain.
D. J. Webb
Ocean Sci., 8, 733–750, https://doi.org/10.5194/os-8-733-2012, https://doi.org/10.5194/os-8-733-2012, 2012
Cited articles
Arakawa, A.: Computational design for long-term numerical integration of the equations of fluid motion: Two-dimensional incompressible flow, J. Computat. Phys., 1, 119–143, 1966.
Arakawa, A. and Lamb, V. R.: A Potential Enstrophy and Energy Conserving Scheme for the Shallow Water Equations, Monthly Weather Rev., 109, 19–36, 1981.
Arbic, B. K., St-Laurent, P., Sutherland, G., and Garrett, C.: On the resonance and influence of the tides in Ungava Bay and Hudson Strait, Geophys. Res. Lett, 34, L17606, ,https://doi.org/10.1029/2007GL030845, 2007.
Arbic, B. K., Karsten, R. H., and Garrett, C.: On Tidal Resonance in the Global Ocean and the Back-Effect of Coastal Tides upon Open-Ocean Tides, Atmos.-Oc., 47, 239–266, 2009.
Brink, K.: Coastal-trapped Waves and Wind-driven Currents over the Continental Shelf, Ann. Rev. Fluid Mechan., 23, 389–412, 1991.
Buchwald, V. T.: Resonance of Poincaré waves on a continental shelf, Austr. J. Mar. Freshwater Res., 31, 451–457, 1980.
Cartwright, D. E., Edden, A. C., Spencer, R., and Vassey, J. M.: The tides of the northeast Atlantic Ocean, Philos. T. R. Soc. Lond., 298, 87–139, 1980a.
Cartwright, D. E., Huthnance, J., Spencer, R., and Vassey, J. M.: On the St Kilda shelf tidal regime, Deep-Sea Res., 27A, 61–70, 1980b.
Clarke, A. J. and Battisti, D. S.: The effect of continental shelves on tides, Deep-Sea Res., 28A, 665–682, 1981.
Egbert, G. and Ray, R.: Significant dissipation of tidal energy in the deep ocean inferred from satellite altimeter data, Nature, 405, 775–778, 2000.
Espelid, T. O., Berntsen, J., and Barthel, K.: Conservation of energy for schemes applied to the propagation of shallow-water inertia-gravity waves in regions with varying depth, Int. J. Numer. Engng., 1521–1545, 2000.
Flather, R. A.: A Tidal Model of the North-west European Continental Shelf, Memoires Societé Royale des Sciences de Lige, 10, 141–164, 1976.
Flather, R. A.: Estimates of extreme conditions of tide and surge using a numerical model of the north-west European continental shelf, Estuarine, Coast. Shelf Sci., 24, 69–93, 1987.
Fong, S. and Heaps, N.: Note on the quarter-wave tidal resonance in the Bristol Channnel, Institute of Oceanographic Sciences, Report No., 63, 15, 1978.
Grignon, L.: Tidal resonances on the North-West European Shelf, Master's thesis, University of Southampton, School of Ocean and Earth Science, 2005.
Heath, R.: Resonant period and Q of the Celtic Sea and Bristol Channel, Estuarine, Coast. Shelf Sci., 12, 291–301, 1981.
Huthnance, J. M.: On Trapped Waves over a Continental Shelf, J. Fluid Mechan., 69, 689–704, 1975.
Huthnance, J. M.: On shelf-sea resonance with application to Brazilian M3 tides, Deep-Sea Res., 27A, 347–366, 1980.
IOC, IHO, and BODC: Centenary Edition of the GEBCO Digital Atlas, published on CD-ROM on behalf of the Intergovernmental Oceanographic Commission and the International Hydrographic Organization as part of the General Bathymetric Chart of the Oceans, British Oceanographic Data Centre, Liverpool, UK, 2003.
Jones, J. E. and Davies, A. M.: An intercomparison between finite difference and finite element (TELEMAC) approaches to modelling west coast of Britain tides, Ocean Dynam., 55, 178–198, 2005.
Kwong, S. C., Davies, A. M., and Flather, R. A.: A three-dimensional model of the principal tides on the European shelf, Prog. Oceanogr., 39, 205–262, 1997.
Le Provost, C., Rougier, G., and Poncet, A.: Numerical Modeling of the Harmonic Constituents of the Tides, with Application to the English Channel, J. Phys. Oceanogr., 11, 1123–1138, 1981.
Madec, G.: NEMO Ocean Engine, Note du Pole de modélisation, No. 27, Institut Pierre-Simon Laplace (IPSL), France, http://www.nemo-ocean.eu/About-NEMO/Reference-manuals, 2008.
Owen, A.: A Three-Dimensional Model of the Bristol Channel, J. Phys. Oceanogr., 10, 1290 – 1302, 1980.
Pingree, R. D. and Griffiths, D. K.: Tidal fronts on the shelf seas around the British Isles, J. Geophys. Res., 83, 4615–4622, 1978.
Sinha, B. and Pingree, R.: The principal lunar semidiurnal tide and its harmonics: baseline solutions for M2 and M4 constituents on the North-West European Continental Shelf, Contin. Shelf Res., 17, 1321–1365, 1997.
Stephens, C. V.: A three-dimensional model for tides and salinity in the Bristol Channel, Contin. Shelf Res., 6, 531–560, 1986.
Uncles, R.: Physical properties and processes in the Bristol Channel and Severn Estuary, Mar. Pollut. Bull., 61, 5–20, 2010.
Webb, D. J.: Green's Function and Tidal Prediction, Rev. Geophys. Space Phys., 12, 103–116, 1973.
Webb, D. J.: A Model of Continental Shelf Resonances, Deep-Sea Res., 23, 1–15, 1976.
Webb, D. J.: Numerical Model of the Tides in the Gulf of Carpentaria and Arafura Sea, Austr. J. Mar. Freshwater Res., 32, 31–44, 1981.
Webb, D. J.: Notes on a 1-D Model of Continental Shelf Resonances, Research and Consultancy Report 85, National Oceanography Centre, Southampton, http://eprints.soton.ac.uk/171197, 2011.
Webb, D. J.: On the Shelf Resonances of the Gulf of Carpentaria and the Arafura Sea, Ocean Science, 8, 733–750, https://doi.org/10.5194/os-8-733-2012, 2012.
Webb, D. J.: On the Impact of a Radiational Open Boundary Condition on Continental Shelf Resonances, National Oceanography Centre, Internal Document 06, National Oceanography Centre, Southampton, http://eprints.soton.ac.uk/349401, 2013