Drift station and buoy observation and monitoring have revealed two major ice circulation systems in the Arctic Ocean - the east to west Transpolar Drift in the Eurasian Arctic (Russian Siberia) and the clockwise Beaufort Gyre north of Alaska and Canada.

The Beaufort Gyre ("rotating pattern") slowly swirls the surface waters of the Arctic basin, turning the Polar Ice Cap along with it. It makes one complete rotation about every 4 years.

The Transpolar Drift carries water and ice from Siberia, across the Pole and down the east coast of Greenland, where it joins the East Greenland current. This current is caused by the inflow from Siberian rivers, and a westerly wind that pushes Arctic surface water eastward into the Atlantic.

How far can something drift in these currents?

In 1979, floating disks were scattered in the Beaufort Sea near Prudhoe Bay, Alaska. This was an experiment to see what might happen if there was an oil spill during shipments from the Alaskan North Slope oil fields.

In 1998, two brothers found a disk while taking a walk on the beach of a Scottish island.

The disk was likely caught in the Beaufort Gyre (Picture: right) where it circled for at least a decade. From there, the Transpolar Drift carried it out of the Arctic Ocean - passing it off to the Greenland current. This would carry it down to the North Atlantic Drift, an extension of the Gulf Stream, which finally deposited it in Scotland - about 3,500 miles / 5,600 km away!

Message on floating disk: "One Dollar Reward on Return of Serial Number with Date Found, Location, Your Name and Address to Geophysics Institute, Univ. of Alaska, Fairbanks."