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The rise of the bulge

Scientists have found an enormous dome in the western Arctic Ocean, full of fresh water. The bulge is thought to be around 8000 cubic meters in size and has risen about 15cm in 10 years.

The image on the right shows the rise of the bulge, rising fast in 10 years. The second picture then shows how a bulge is made.

"In the western Arctic, the Beaufort Gyre is driven by a permanent anti-cyclonic wind circulation. It drives the water, forcing it to pile up in the centre of gyre, and this domes the sea surface," explained lead author Dr Katharine Giles from the Centre for Polar Observation and Modelling (CPOM) at University College London to the BBC.

The making of the bulgeAn ESA satellite was used to discover the bulge. Most of the fresh water is coming from the Russian side of the Arctic.

Winds and currents have transported this fresh water around the ocean until it has been pulled into the gyre. The volume currently held in the circulation probably represents about 10% of all the fresh water in the Arctic, according to BBC.

If the fresh water were to enter the North Atlantic in large volumes, the concern would be that it might disturb the currents that have such a great influence on European weather patterns.

These currents draw warm waters up from the tropics, maintaining milder temperatures in winter than would ordinarily be expected at northern European latitudes.

"The ice is now much freer to move around," said Dr Giles to the BBC.

"So, as the wind acts on the ice, it's able to pull the water around with it. Depending on how ridged the surface of ice is or how smooth the bottom of the ice is - this will all affect the drag on the water."

"If you have more leads, this also might provide more vertical ice surfaces for the wind to blow against."

Sources

BBC