Arctic dips as global waters rise

A Dutch-UK team made the discovery after analysing radar altimetry data gathered by Europe's ERS-2 satellite. …

Next year has been designated International Polar Year, and major oceanographic expeditions are planned to take research vessels into the northern region to sample its icy waters.

"This may provide clues as to what is causing the changes we're seeing," explained co-researcher Dr Seymour Laxon [UCL Earth Sciences]. "I think it's a true statement to say the Arctic Ocean is the least well understood body of water out there."

The recent trend could be linked to changes in the temperature and salinity (saltiness) of Arctic waters. This would have to be investigated, he said. …

Dr Laxon said getting a clearer understanding of Arctic Ocean behaviour was important to the topical issue of ice melt in the region. Recent years have seen a dramatic pull-back in the extent of summer ice and the models do not fully account for the changes that are being observed.

"One thing that is known very poorly is the amount of heat that comes from the ocean into the ice. It could be an important factor in the retreat of ice," the UCL scientist said. …

Jonathan Amos, BBC News