Freshwater pool in western Arctic
22 Mar 2012 by Evoluted New Media
A strong Arctic wind is responsible for an enormous dome of freshwater in the western Arctic Ocean say researchers who have been monitoring sea-surface height from 1995 to 2010.
Using the European Space Agency satellites ERS-2 and Envisat, researchers from the Centre for Polar Observation and Modelling (CPOM) at UCL and the National Oceanography Centre (NOC) measured sea-surface height over the western Arctic.
Researchers believe that the dome may be a result of strong Arctic winds accelerating a great clockwise ocean circulation called the Beaufort Gyre, causing the ocean to bulge upwards. They calculated that since 2002, the sea surface has risen by 15cm and the volume of freshwater has swollen by roughly 8,000 cubic kilometres – around 10% of all the freshwater in the Arctic Ocean. A reversal of the wind could cause this water to spill out into the rest of the Arctic and even the north Atlantic.
“Satellite data has shown us that a dome of fresh water has been building up in the western Arctic over the past 15 years due to the wind,” said Dr Katharine Giles from CPOM. “Our findings suggest that a reversal of the wind could result in the releases of this freshwater to the rest of the Arctic Ocean and even beyond.”
This could cool Europe down by slowing a key ocean current derived from the Gulf Stream, which keeps the continent relatively mild compared with countries at similar latitudes.
Earlier studies had suggested that the volume of freshwater had been increasing in the region, while other studies found that less freshwater reached the Atlantic than expected over the same period of time. These findings suggest that the water is concentrated in the Beaufort Gyre and can’t spill out into the Atlantic.
Giles – lead author of the study published in Nature Geoscience – says the results also suggest something else is going on.
“When we looked at our data on a year-to-year basis we noticed that the change in the sea surface height did not always follow what the wind was doing,” Giles said. “We thought about reasons why this might happen. One idea is that sea ice forms a barrier between the atmosphere and the ocean. So as the sea-ice cover changes, the effect of the wind on the ocean might also change.”
