What are the mysterious waves in the Arctic?

A puzzling arc was discovered in the waters of a Greenland fjord littered with pieces of drifting ice. Experts say there are a number of explanations for this strange phenomenon, but we may never know what causes it.

The satellite photo above shows a mysterious arc in a fjord , covered with icebergs deep in the Arctic.

Researchers discovered a mysterious wave (white arc in this photo) rippling on the surface of the Greenland fjord last year. (Photo: NASA Earth Observatory/Wanmei Liang/Landsat).

A thin white arc

Itilliarsuup Kangerlua Fjord is part of the Uummannaq fjord system in West Greenland, about 740km north of the country's capital Nuuk. According to NASA's Earth Observatory, the narrow waterway, about 2.6km long, is formed by two glaciers, Sisoortartukassak and Kangilleq, separated by a small island at the foot of the fjord.

In summer, the fjord's surface becomes dotted with thousands of small pieces of icebergs that have flaked off from the glacier, making the water look like a star from a telescope image when viewed from above. However, the most interesting feature in the photo is a thin white arc stretching across the fjord.

According to the Earth Observatory, this arc is most likely a displacement wave propagating up the fjord away from the ice sheet. The wave could be caused by a large chunk of ice breaking off from the Kangilleq glacier and falling into the water - like the ripples you see when you throw a rock into a still lake.

Josh Willis, an oceanographer at NASA's Jet Propulsion Laboratory, said: 'The perfect shape of the arc and direction of the waves are similar to calving events observed on other glaciers '.

Dan Shugar, a geomorphologist at the University of Calgary, and Mike Wood, a glaciologist at the Moss Landing Marine Laboratory in California, USA, also believe that the arc is the result of a calving event, according to the Radio observe the Earth.

However, the wave could also have been caused by an "underwater current" coming from the Kangilleq glacier, Willis added. Such plumes are created from fresh melt water entering the fjord's salty waters from beneath the glacier and rising to the surface, displacing the water around it.