We brought a number (35) of RAFOS floats on the cruise. These floats will be deployed over the slopes of the Mid Atlantic Ridge and the Greenland continental shelf. The floats will track the water motion at depth. Today’s floats were ballasted for 2200 m, 2000 m and 1800 m depth. At this depth (at 34° W) we expect to follow the Iceland Scotland Overflow Water (ISOW, sometimes also called North East Atlantic Deep Water or NEADW). This dense water flows over the Iceland-Faroe Ridge and then follows the topography of the Mid Atlantic Ridge. The ISOW is one of the dense southward flowing waters that compensate the surface currents carrying warm water north.

The floats are launched (deepest one first) through a tube from the aft deck and shoot straight down. We will not hear from them for two years. In the meantime they will track the current and listen to the moored sound sources. Sound can carry for hundreds of kilometers under water. Ten sound sources are present in the North Atlantic for this project, covering the area between Iceland and 50°N.