Posts Tagged ‘ocean current’

Stronger Ocean Currents Speed Melting Of Antarctic Ice

June 27, 2011 Comments off


Stronger ocean currents beneath West Antarctica’s Pine Island Glacier Ice Shelf are eroding the ice from below, speeding the melting of the glacier as a whole, according to a new study in Nature Geoscience. A growing cavity beneath the ice shelf has allowed more warm water to melt the ice, the researchers say—a process that feeds back into the ongoing rise in global sea levels. The glacier is currently sliding into the sea at a clip of four kilometers (2.5 miles) a year, while its ice shelf is melting at about 80 cubic kilometers a year – 50 percent faster than it was in the early 1990s – the paper estimates.

A major glacier is undermined from below: upwelling seawater along parts of Pine Island Glacier Ice Shelf has carved out caves in the ice and drawn wildlife like this whale.

Credit: Maria Stenzel, all rights reserved.

“More warm water from the deep ocean is entering the cavity beneath the ice shelf, and it is warmest where the ice is thickest,” said study’s lead author, Stan Jacobs, an oceanographer at Read more…

Rogue wave frequency increases

April 25, 2011 Comments off


The Norwegian tanker Wilstar after being struck by a large wave in 1974. (Contributed photo)

The German container ship MS München left Bremerhaven, Germany, on a cold day in late 1978 headed for Savannah, Ga. On Dec. 12, the ship, two and a half football fields long and described as unsinkable, vanished after one unintelligible distress call.

All that was found in a wide search of the general area was some scattered debris and an unlaunched lifeboat that was originally secured on the deck 65 feet above the water line. Its attachment pins had been “twisted as though hit by an extreme force.” The best guess at the time was that the ship had been struck by a very large wave.

While seaman for many years have described huge waves or walls of water at sea, they weren’t usually given much credence until recently. Encounters with such large waves have become more frequent over the past 15 years or so, however, indicating that perhaps these weren’t all just sailor’s exaggerations or nightmares.

In February 1995, the Queen Elizabeth II encountered what was described as a 95-foot wall of water in the North Atlantic. The ship’s captain said it “came out of the darkness” and “looked like the White Cliffs of Dover.” He was able to determine the wave’s height because the crest was level with the ship’s bridge. The wave broke over the bow with explosive force and smashed many of the windows and part of its forward deck. That same year, an oil platform in the North Sea with a wave gauge measured a single rogue Read more…