The Overflow Transport East of Iceland

East of Iceland, there are several areas in which overflow of dense water passes from the Norwegian Sea across the Iceland-Scotland Ridge into the Atlantic Ocean. Together, these overflows have been estimated (Hansen and Østerhus 2000) to yield a volume transport of similar magnitude to that through the Denmark Strait (Fig. 18.1). These eastern overflows thus contribute about 50% of the dense overflow from the Arctic Mediterranean into the North Atlantic.

The largest eastern overflow occurs in the deepest passage across the Greenland-Scotland Ridge, the Faroe Bank Channel, with a sill depth of 840 m. Some dense water also crosses the shallower ridges between Iceland and Scotland, the Iceland–Faroe Ridge with sill depth around 480 m, and the Wyville Thomson Ridge with a sill depth around 600 m.

During the ASOF period, observations of the eastern overflows were included in the ASOF-MOEN project. These observations included extension of the measurements of dense overflow through the Faroe Bank Channel and new instrumental records have been obtained for the Iceland–Faroe Ridge and Wyville Thomson Ridge.

Reviews on the history of overflow research and its accomplishments are given in Saunders (2001) and Hansen and Østerhus (2000), who focus on the eastern overflows. In this chapter, we offer a brief overview of the eastern overflows, including results from observations made during the last decade in a series of projects: Nordic WOCE, VEINS, ASOF-MOEN.