Ocean currents of the Νorth Atlantic © 2018-2025 Manolis Koutlis, PhD

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Ocean currents of the Νorth Atlantic

Sea travel to the North Atlantic Ocean are central to this series of tales. Therefore, Atlantic sailing conditions are of particular importance, especially with regard to the ocean currents, for which it would be useful to know some of their basic features, since they determined to a large extent the paths of the sea routes.

The Gulf Stream

M.F. Maury’s “Physical Geography of the Sea”, 1 published in 1856, has been an oceanography and navigation reference book for decades. Maury describes the Gulf Stream as follows:

There is a river in the ocean. In the severest droughts it never fails, and in the mightiest floods it never overflows. Its banks and its bottoms are of cold water, while its current is of warm. The Gulf of Mexico is its fountain, and its mouth is in the Arctic Seas. It is the Gulf Stream. There is in the world no other such majestic flow of waters. Its current is more rapid than the Mississippi or the Amazon, and its volume more than a thousand times greater.

Its waters, as far out from the Gulf as the Carolina coasts, are of an indigo blue. They are so distinctly marked that their line of junction with the common sea-water may be traced by the eye.

The main features of Gulf Stream include:

  • Maximum speed: 9km/h, or 216km per 24h.
  • Average Speed: 6.4km/h, or 154km per 24h.
  • Minimum speed (northern branches): 1.6km/h, or 38km per 24h.
  • Carries about 10 million cubic meters of water per second, which is greater than the quantity transported from all the rivers of the world together.
  • The current is warm. At many points in its flow the temperature is as much as 10°C higher than that of neighboring waters, which often results in the formation of fog above the current’s flow.
  • The main branches of the Gulf Stream (the largest of which is the N. Atlantic current) are depicted in a simplified form on map below in dark red. Among other sources, the Gulf Stream is fed by the North Equatorial Current which starts from the west coast of Africa and moves from east to west. These two currents create the so called North Atlantic Gyre, that flows in the cyclic route shown in the map. 2,3,4,5,6,7,8

The East Greenland and Labrador currents

The cold current of East Greenland and the cold stream created in Labrador travel from north to south along the North American coasts, influencing the climate of these areas and contributing to their biodiversity. On map above, these current flows are shown in cyan color.

The main data known about these currents are:

  • They are cold, with temperatures below 0°C, and have low salinity.
  • They are restricted to the continental shelf and reaches depths slightly more than 600m.
  • The volume of water transport varies from about 3.5 to 5.4 million cubic meters per second, and carry several thousand icebergs each year to the south.
  • They are of the slowest currents of the ocean. They usually run at speeds ranging from 0.4 km/h to 2-3 km/h, that is, 10-72km per 24h.

Bibliography

  1. Maury, M.F. (1856). ‘The Physical Geographyof the Sea’, New York: Harper & Brothers
  2. Eldevik, Τ. Straneο, F. Sandø, A. Br. Furevik, T.(2005). ‘Pathways and export of Greenland Sea Water’, in The Nordic Seas: anintegrated perspective, Washington DC: American Geophysical Union GeophysicalMonograph Series. 89-104
  3. Walczowski, W. (2014). ‘Atlantic Water in theNordic Seas’, GeoPlanet: Earth and Planetary Sciences, Springer. ISBN978-3-319-01278-0
  4. Maritime Safety Office, NationalGeospatial-Intelligence Agency, ‘Pilot Chart of the North Atlantic Ocean’, ( www.msi.nga.mil )
  5. Bowditch, Ν. (2010). ‘American PracticalNavigator’, Paradise Cay Publications.
  6. Johnson, J. Stevens, I. (2000). ‘A fineresolution model of the eastern North Atlantic between the Azores, the CanaryIslands and the Gibraltar Strait’, Deep-Sea Research, I 47 pp. 875-899, PERGAMON
  7. Klein, B. Siedler, G. (1989). ‘On the Origin ofthe Azores Current’, Journal of Geophysical Research, 15 May, vol. 94,no. C5, pp. 6159-6168
  8. Barton, E. D. (2001). ‘Canary and Portugalcurrents’, in Steele, J.H. and Turekian, K.K. and Thorpe, S.A. (eds), Encyclopediaof Ocean Sciences, pp. 380-