Oceanography The Official Magazine of
The Oceanography Society
Volume 26 Issue 02

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Volume 26, No. 2
Pages 156 - 163


The Extended Ellett Line: Discoveries from 65 Years of Marine Observations West of the UK

By N. Penny Holliday  and Stuart A. Cunningham 
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Article Abstract

Shallow and deep branches of the Meridional Overturning Circulation pass through the Rockall Trough and Iceland Basin where measurements of salinity and temperature have been made for 65 years. There is a very small number of decadal-scale time series in the world ocean, so this long-term data collection represents an unusually rich resource for climate science. The early data sets of surface temperature and salinity collected by ocean weather ships provided a previously unseen picture of the annual cycle of these properties as well as multiyear variability. In 1975, regular, repeated sampling of the full-depth deep ocean began to reveal the variability of water masses and details of their circulation. Here, we describe the history of sampling in the region and the main scientific discoveries about ocean circulation and variability made using these data. Continuing sustained observing of temperature, salinity, nutrients, and carbon from ships will contribute to the international focus in the subpolar gyre over the next decade.


Holliday, N.P., and S.A. Cunningham. 2013. The Extended Ellett Line: Discoveries from 65 years of marine observations west of the UK. Oceanography 26(2):156–163, https://doi.org/10.5670/oceanog.2013.17.


Belkin, I.M., S. Levitus, J. Antonov, and S.-V. Malmberg. 1998. “Great Salinity Anomalies” in the North Atlantic. Progress in Oceanography 41:1–68, https://doi.org/10.1016/S0079-6611(98)00015-9.

Booth, D.A. 1988. Eddies in the Rockall Trough. Oceanologica Acta 11:213–219.

Booth, D.A., and D.J. Ellett. 1983. The Scottish continental slope current. Continental Shelf Research 2:127–146, https://doi.org/10.1016/0278-4343(83)90012-2.

Bryden, H.L., C. Robinson, and G. Griffiths. 2012. Changing currents: A strategy for understanding and predicting the changing ocean circulation. Philosophical Transactions of the Royal Society A 370:5,461–5,479, https://doi.org/10.1098/rsta.2012.0397.

Cunningham, S.A., and T.W.N. Haine. 1995. Labrador Sea Water in the eastern North Atlantic. Part II: Mixing dynamics and the advective-diffusive balance. Journal of Physical Oceanography 25:666–678, https://doi.org/10.1175/1520-0485(1995)025<0666:LSWITE>2.0.CO;2.

Dickson, B., J. Meincke, and W.R. Turrell. 2003. Introduction. Pp. 1–12 in Hydrobiological Variability in the ICES Area, 1990–1999. ICES Marine Science Symposia, vol. 219.

Dickson, R.R., J. Meincke, S.-A. Malmberg, and A.J. Lee. 1988. The “great salinity anomaly” in the northern North Atlantic 1968–1982. Progress in Oceanography 20:103–151, https://doi.org/10.1016/0079-6611(88)90049-3.

Dunstone, N.J., D.M. Smith, and R. Eade. 2011. Multi-year predictability of the tropical Atlantic atmosphere driven by the high latitude North Atlantic Ocean. Geophysical Research Letters 38, L14701, https://doi.org/10.1029/2011GL047949.

Dye, S., G.D. Nolan, and A. Beszczynska-Möller. 2012. ICES Report on Ocean Climate 2011. ICES Cooperative Research Report 314, 77 pp. Available online at: http://info.ices.dk/pubs/crr/crr314/ICRR 314-web.pdf (accessed April 17, 2013).

Ellett, D.J. 1978. Sub-surface Temperatures at the Scottish Continental Slope. Scottish Marine Biological Association, Internal Report 2, 17 pp.

Ellett, D.J. 1980. Long-Term Water-Mass Variations in the North-eastern Atlantic. International Council for the Exploration of the Seas, CM Report, 1980/C9, 17 pp.

Ellett, D.J. 1982. Long-term water-mass changes to the west of Britain. Pp. 245–254 in Time Series of Ocean Measurements. D. Ellett, ed., World Climate Program Report 21, Geneva, Switzerland.

Ellett, D.J., and J.H.A. Martin. 1973. The physical and chemical oceanography of the Rockall Channel. Deep Sea Research 20:585–625, https://doi.org/10.1016/0011-7471(73)90030-2.

Ellett, D.J., A. Edwards, and R. Bowers. 1986. The hydrography of the Rockall Channel: An overview. Proceedings of the Royal Society of Edinburgh 88:61–81, https://doi.org/10.1017/S0269727000004474.

Ellett, D.J., and S.R. Jones. 1994. Surface Temperature and Salinity Time-Series From the Rockall Channel. Fisheries Research Data Report 36, MAFF Directorate of Fisheries Research, Lowestoft, 24 pp.

Hátún, H., M.R. Payne, G. Beaugrand, P.C. Reid, A.B. Sando, H. Drange, B. Hansen, J.A. Jacobsen, and D. Bloch. 2009. Large bio-geographical shifts in the north-eastern Atlantic Ocean: From the subpolar gyre, via plankton, to blue whiting and pilot whales. Progress in Oceanography 80:149–162, https://doi.org/10.1016/j.pocean.2009.03.001.

Hátún, H., A.B. Sando, H. Drange, B. Hansen, and H. Valdimarsson. 2005. Influence of the Atlantic subpolar gyre on the thermohaline circulation. Science 309:1,841–1,844, https://doi.org/10.1126/science.1114777.

Holliday, N.P. 2002. Interannual variability of the circulation and ventilation of the North Atlantic subpolar gyre. PhD Thesis, University of Liverpool, 231 pp.

Holliday, N.P. 2003. Air-sea interaction and circulation changes in the northeast Atlantic. Journal of Geophysical Research 108, C8, L3259, https://doi.org/10.1029/2002JC001344.

Holliday, N.P., S.L. Hughes, S. Bacon, A. Beszczynska-Möller, B. Hansen, A. Lavin, H. Loeng, K.A. Mork, S. Østerhus, T. Sherwin, and W. Walczowski. 2008. Reversal of the 1960s to 1990s freshening trend in the northeast North Atlantic and Nordic Seas. Geophysical Research Letters 35, L03614, https://doi.org/10.1029/2007GL032675.

Holliday, N.P., R.T. Pollard, J.F. Read, and H. Leach. 2000. Water mass properties and fluxes in the Rockall Trough, 1975–1998. Deep Sea Research Part I 47:1,303–1,332, https://doi.org/10.1016/S0967-0637(99)00109-0.

Holliday, N.P., M.J. Yelland, R. Pascal, V.R. Swail, P.K. Taylor, C. Griffiths, and E.C. Kent. 2006. Were extreme waves in the Rockall Trough the largest ever recorded? Geophysical Research Letters 33, L05613, https://doi.org/10.1029/2005GL025238.

Howe, J.A., M.S. Stoker, and K.J. Woolfe. 2001. Deep-marine seabed erosion and gravel lags in the northwestern Rockall Trough, North Atlantic Ocean. Journal of the Geological Society 158:427–438, https://doi.org/10.1144/jgs.158.3.427.

Huthnance, J.M. 1995. Circulation, exchange and water masses at the ocean margin: The role of physical processes at the shelf edge. Progress in Oceanography 35:353–431, https://doi.org/10.1016/0079-6611(95)80003-C.

Huthnance, J.M., and W.J. Gould. 1989. On the Northeast Atlantic slope current. Pp. 76–81 in Poleward Flows Along Eastern Ocean Boundaries. S.J. Neshyba, C.N.K. Mooers, R.L. Smith, and R.T. Barber, eds, Springer-Verlag.

Hydes, D.J., R.J. Gowen, N.P. Holliday, T. Shammon, and D. Mills. 2003. External and internal control of winter concentrations of nutrients (N, P and Si) in north-west European shelf waters. Estuarine Coastal and Shelf Science 59:151–161, https://doi.org/10.1016/j.ecss.2003.08.004.

Inall, M.E., P.A. Gillibrand, C. Griffiths, N. MacDougall, and K. Blackwell. 2009. On the oceanographic variability of the North-West European Shelf to the West of Scotland. Journal of Marine Systems 77:210–226, https://doi.org/10.1016/j.jmarsys.2007.12.012.

Johnson, C., T. Sherwin, D. Smythe-Wright, T. Shimmield, and W. Turrell. 2010. Wyville Thomson Ridge Overflow Water: Spatial and temporal distribution in the Rockall Trough. Deep Sea Research Part I 57:1,153–1,162, https://doi.org/10.1016/j.dsr.2010.07.006.

Pollard, R.T., J.F. Read, N.P. Holliday, and H. Leach. 2004. Water masses and circulation pathways through the Iceland Basin during Vivaldi 1996. Journal of Geophysical Research 109, C04004, https://doi.org/10.1029/2003JC002067.

Read, J.F., and W.J. Gould. 1992. Cooling and freshening of the subpolar North Atlantic Ocean since the 1960s. Nature 360:55–57, https://doi.org/10.1038/360055a0.

Reid, P.C., N.P. Holliday, and T.J. Smyth. 2001. Pulses in the eastern margin current and warmer water off the northwest European shelf linked to North Sea ecosystem changes. Marine Ecology Progress Series 215:283–287, https://doi.org/10.3354/meps215283.

Sherwin, T., J.F. Read, N.P. Holliday, and C. Johnson. 2012. The impact of changes in the North Atlantic gyre distribution on water mass characteristics in the Rockall Trough. ICES Journal of Marine Science 69:751–757, https://doi.org/10.1093/icesjms/fsr185.

Sy, A., M. Rhein, J.R.N. Lazier, K.P. Koltermann, J. Meincke, A. Putzka, and M. Bersch. 1997. Surprisingly rapid spreading of newly formed intermediate waters across the North Atlantic Ocean. Nature 386:675–679, https://doi.org/10.1038/386675a0.

Turrell, W.R., G. Slesser, R.D. Adams, R. Payne, and P.A. Gillibrand. 1999. Decadal variability in the composition of Faroe Shetland Channel bottom water. Deep Sea Research 46:1–25, https://doi.org/10.1016/S0967-0637(98)00067-3.

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