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guardian Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Jan-21-09 08:45 PM
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Antarctic Ice Sheet Gains Mass
East Antarctic Ice Sheet Gains Mass and Slows Sea Level Rise, Study Finds
May 20th, 2005 in Space & Earth science /

Results Reported in Online Edition of Science Suggest Increasing Snowfall is Likely Cause

Current estimates indicate that the global sea level is rising due to global warming and the shrinkage of terrestrial, or land-based, ice. Recent scientific studies have shown that a variety of terrestrial ice sources, such as the Greenland ice sheet, the West Antarctic ice sheet and Alaskan mountain glaciers, are contributing significant amounts to the global sea-level rise. However, in a study to appear in this week's online edition of Science, a researcher at the University of Missouri-Columbia has found that the interior of the East Antarctic ice sheet is actually gaining mass.

From 1992 to 2003, Curt Davis, MU professor of electrical and computer engineering, and his team of researchers observed 7.1 million kilometers of the ice sheet, using satellites to measure changes in elevation. They discovered that the ice sheet's interior was gaining mass by about 45 billion tons per year, which was enough to slow sea level rise by .12 millimeters per year. The interior of the ice sheet is the only large terrestrial ice body that is likely gaining mass rather than losing it, Davis said.

"Many recent studies have focused on coastal ice sheet losses and their contributions to sea level rise," Davis said. "This study suggests that the interior areas of the ice sheet also can play an important role. In particular, the East Antarctic ice sheet is the largest in the world and contains enough mass to raise sea level by more than 50 meters. Thus, only small changes in its interior can have a significant affect on sea level."

The study, funded by NASA's Cryospheric Processes Program and the National Science Foundation's Antarctic Glaciology Program, suggests that increased precipitation was the likely cause of the gain. This was based on comparisons with precipitation model predictions over the same period of time. The most recent U.N. Intergovernmental Panel on Climate Change reported that Antarctica would gain mass due to increased precipitation in a warming climate. However, the study made no direct link to global warming.

"We need more ice core measurements from East Antarctica to determine if this increased precipitation is a change from the past or part of natural variability," said Joe McConnell of the Desert Research Institute in Reno, Nev., who co-authored the study.

The researchers used satellite radar altimeters from the European Space Agency's ERS-1 and ERS-2 satellites to make 347 million elevation-change measurements between June 1992 to May 2003.

The research team found there was a strong correlation between the predicted precipitation trends and measured elevation change over the 11-year period for the ice sheet, which indicated that East Antarctica's interior was likely gaining mass due to the increased precipitation. The results, though, did not assess the overall contribution of the entire Antarctic ice sheet to sea level rise.

"Ice sheet response to climate change is a complex process that is difficult to measure and even more difficult to predict," Davis said. "The overall contribution of the Antarctic ice sheet to global sea-level change will depend on how mass changes in the ice sheet's interior balance mass changes from the coastal areas."

Source: University of Missouri
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xchrom Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Jan-21-09 08:47 PM
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1. recommend
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Name removed Donating Member (0 posts) Send PM | Profile | Ignore Wed Jan-21-09 08:48 PM
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2. Deleted sub-thread
Sub-thread removed by moderator. Click here to review the message board rules.
 
WheelWalker Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Jan-21-09 08:49 PM
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3. The systems are too complex to model, IMO.
:shrug:
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happyslug Donating Member (1000+ posts) Send PM | Profile | Ignore Thu Jan-22-09 12:09 PM
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9. But most Global Warming Models show an increase in the East Antarctic Ice Sheet
The problem is NOT the East Antarctic Ice Sheet (EAIS) but the smaller, less stable, and grounded below sea level WEST Antarctic Ice Sheet AND the Greenland Ice Sheets. While the EAIS, in most Computer weather models. is expected to expand do to increase participation landing on it in the form of Snow, the WAIS and the Greenland Ice sheet are shown by the same computer models as decreasing in size.

THe reason for this is the EAIS is on the HIGHEST Continent in the world (The Himalayas are taller then the Antarctic Mountains, but the Himalayas are offset by the flatness of Siberia to make Antarctica the TALLEST Continent. The Antarctic has the HIGHEST overall height given its high flat areas compared to other Continent's flat area. This leads to the Second reason for the the EAIS to expand, it is grounded well ABOVE sea level (On the other hand the WAIS is grounded BELOW Sea level so the overall sea temperature's affects the WAIS directly but NOT the EAIS).

The third reason is EAIS is completely within the Antarctic Circle (as is the WAIS) but the Greenland Ice Sheet reaches down below the Arctic Circle).

My point is the Models do reflect that the EAIS will expand, but that has little or nothing to do with sea level raise, which will raise do to the affect Global Warming has on the WAIS and the Greenland Ice Sheet.

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bluedawg12 Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Jan-25-09 10:35 AM
Response to Reply #9
11. Yup. "losses,were primarily concentrated in West Antarctica"
http://earthobservatory.nasa.gov/Newsroom/view.php?old=...
>>Rignot said the losses, which were primarily concentrated in West Antarctica's Pine Island Bay sector and the northern tip of the Antarctic Peninsula, are caused by ongoing and past acceleration of glaciers into the sea. This is mostly a result of warmer ocean waters, which bathe the buttressing floating sections of glaciers, causing them to thin or collapse. "Changes in Antarctic glacier flow are having a significant, if not dominant, impact on the mass balance of the Antarctic ice sheet," he said.

To infer the ice sheet's mass, the team measured ice flowing out of Antarctica's drainage basins over 85 percent of its coastline. They used 15 years of satellite radar data from the European Earth Remote Sensing-1 and -2, Canada's Radarsat-1 and Japan's Advanced Land Observing satellites to reveal the pattern of ice sheet motion toward the sea. These results were compared with estimates of snowfall accumulation in Antarctica's interior derived from a regional atmospheric climate model spanning the past quarter century.

The team found that the net loss of ice mass from Antarctica increased from 112 (plus or minus 91) gigatonnes a year in 1996 to 196 (plus or minus 92) gigatonnes a year in 2006. A gigatonne is one billion metric tons, or more than 2.2 trillion pounds. These new results are about 20 percent higher over a comparable time frame than those of a NASA study of Antarctic mass balance last March that used data from the NASA/German Aerospace Center Gravity Recovery and Climate Experiment. This is within the margin of error for both techniques, each of which has its strengths and limitations.

Rignot says the increased contribution of Antarctica to global sea level rise indicated by the study warrants closer monitoring.<<


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iamthebandfanman Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Jan-21-09 08:52 PM
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4. wasnt this proclaimed last winter?
only to find out the ice had formed 2 months later than usual and went away quicker than normal?
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DCKit Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Jan-21-09 08:57 PM
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5. Yay!!! We'll replace those thousands of square miles of lost ice sheets...
in no time at all.
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AndyA Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Jan-21-09 10:19 PM
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6. May 20th, 2005?
Why are you posting an article that is almost 4 years old?
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kristopher Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Jan-21-09 10:52 PM
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7. Serious question
Why are you posting these writings here?
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Richard D Donating Member (1000+ posts) Send PM | Profile | Ignore Thu Jan-22-09 01:40 AM
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8. Um
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bluedawg12 Donating Member (1000+ posts) Send PM | Profile | Ignore Sun Jan-25-09 10:31 AM
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10. Antarctic Ice Loss Speeds Up, Nearly Matches Greenland Loss
http://earthobservatory.nasa.gov/Newsroom/view.php?old=...

Antarctic Ice Loss Speeds Up, Nearly Matches Greenland Loss

January 23, 2008

Ice loss in Antarctica increased by 75 percent in the last 10 years due to a speed-up in the flow of its glaciers and is now nearly as great as that observed in Greenland, according to a new, comprehensive study by NASA and university scientists.

In a first-of-its-kind study, an international team led by Eric Rignot of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the University of California, Irvine, estimated changes in Antarctica's ice mass between 1996 and 2006 and mapped patterns of ice loss on a glacier-by-glacier basis. They detected a sharp jump in Antarctica's ice loss, from enough ice to raise global sea level by 0.3 millimeters (.01 inches) a year in 1996, to 0.5 millimeters (.02 inches) a year in 2006... read more.

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