Early Evidence for the Iceland-Faroe Front?
This chart is a subsection of Carta Marina, published in Venice in 1539 by Olaus Magnus. The map as a whole is described as 'A map of the Scandinavian countries and the Wonders that exist there'. Only two copies of this map are known: one is located at Staats-Bibliothek in Munich, Germany, and the other is at the University of Uppsala, Sweden.
This portion of the map covers the eastern North Atlantic with Greenland and Iceland at the top, Scotland and the Hebrides at the bottom, and the Faroes, Orkneys and Shetland islands in between.
Look at the waters east of Iceland and north of the Faroes and you'll notice a string of eddies whereas elsewhere the waters in the North Atlantic and Nordic Seas are essentially free of eddies. Why is this? The conjecture is that these eddies coincide with the path of the Iceland-Faroe Front, a major boundary between the warm waters of the north-east Atlantic and the southern Norwegian Sea. This front meanders considerably, with peak surface velocities in the vicinity of 0.5 m/s.
We do know that there was considerable traffic between the west coast of Norway and Iceland beginning in the 900s. The location of the Iceland-Faroe Front east of Iceland and west of Norway is such that mariners could hardly have avoided it. Certainly the sharp temperature contrast would have been evident and one cannot preclude that the Vikings and other Medieval mariners learned to sail with or avoid the warm waters when sailing east or west, respectively.
A recent paper that nicely summarizes our knowledge of the Iceland-Faroe Front was written by Bogi Hansen and Svein Østerhus in Progress in Oceanography, volume 45, pages 109-208.
For a full discussion of the above, please read "Ocean Eddies in the 1539 Carta Marina by Olaus Magnus", an article by Tom Rossby and Peter Miller that was published in Oceanography, the official magazine of The Oceanography Society, Vol. 16(4). A reduced resolution copy can be obtained here.
"Ancient mariners surprise oceanographers", press release, National Environmental Research Council (NERC), UK (April 29, 2004).
"Ancient map captures ocean front", BBC News - London, England, UK (May 5, 2004).
sea chart was in line with current thinking", Telegraph.co.uk -
London, England, UK (May 5, 2004).
"The 1539 Carta marina by
Olaus Magnus, an exiled Swedish priest", op-ed, Providence Journal, Providence,
Rhode Island (July 11, 2004).
Additional links to related articles in Science, Nature,New
Scientist, and other sites can be found on the website for the
Remote Sensing Group at Plymouth Marine Laboratory here.
A colorized version of Carta marina can be seen at http://bell.lib.umn.edu/map/OLAUS/carta.html.