Featured Posts

To top

Ocean Tag

28 Sep

An ocean inside Earth? Water hundreds of kilometers down

The transition zone (TZ) is the name given to the boundary layer that separates the Earth's upper mantle and the lower mantle. It is located at a depth of 410 to 660 kilometres. The immense pressure of up to 23,000 bar in the TZ causes the olive-green mineral olivine, which constitutes around 70 percent of the Earth's upper mantle and is also called peridot, to alter its crystalline structure. At the upper boundary of the transition zone, at a depth of about 410 kilometres, it is converted into denser wadsleyite; at 520 kilometres it then metamorphoses into even denser ringwoodite. "These mineral transformations greatly hinder the movements of rock in the mantle," explains Prof. Frank Brenker from the Institute for Geosciences...
Continue reading
17 Sep

Researchers go ‘outside the box’ to delineate major ocean currents

For the first time University of Rochester researchers have quantified the energy of ocean currents larger than 1,000 kilometers. In the process, they and their collaborators have discovered that the most energetic is the Antarctic Circumpolar Current, some 9,000 kilometers in diameter. The team, led by Hussein Aluie, associate professor of mechanical engineering, used the same coarse-graining technique developed by his lab to previously document energy transfer at the other end of the scale, during the "eddy-killing" that occurs when wind interacts with temporary, circular currents of water less than 260 kilometers in size. These new results, reported in Nature Communications, show how the coarse-graining technique can provide a new window for understanding oceanic circulation in all its multiscale complexity, says lead author...
Continue reading
10 Sep

Southern Ocean takes on the heat of climate change

In the past 50 years, the oceans have absorbed more than 90% of the excess heat caused by our carbon dioxide emissions, with one ocean absorbing the vast majority. "The Southern Ocean dominates this ocean heat uptake, due in part to the geographic set-up of the region," said UNSW PhD candidate Maurice Huguenin, the lead author of the new study published today in Nature Communications. "Antarctica, which is surrounded by the Southern Ocean, is also surrounded by strong westerly winds," Mr Huguenin said. "These winds influence how the waters absorb heat, and around Antarctica they can exert this influence while remaining uninterrupted by land masses -- this is key to the Southern Ocean being responsible for pretty much all of the net global ocean...
Continue reading