Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



Detection, Not Warming, Behind Increase In Large Antarctic Icebergs

big but pretty much normal
Provo - Oct 25, 2002
Contrary to an opinion held by some researchers, a new analysis of more than 20 years of historical data has found no evidence that the increasing number of large icebergs off Antarctica's coasts is a result of global warming trends.

"The dramatic increase in the number of large icebergs as recorded by the National Ice Center database does not represent a climatic change," said Brigham Young University electrical engineering professor David Long, who, with Cheryl Bertoia of the U. S. National Ice Center, reports these findings in the new issue of EOS Transactions, a publication of the American Geophysics Union. "Our reanalysis suggests that the number of icebergs remained roughly constant from 1978 to the late 1990s."

Using BYU's supercomputers, Long enhanced images of the waters around Antarctica transmitted by satellite.

Comparing this data to records from the federal government's National Ice Center, which tracks icebergs larger than ten miles on one side, he determined that previous tracking measures were inadequate, resulting in a gross undercounting.

An additional recent spike in large icebergs can be explained by periodic growth and retraction of the large glaciers that yield icebergs every 40 to 50 years, he said, noting previous research done by other scientists.

"Dr. Long's analysis shows that the increase is only an 'apparent increase,' and that it is premature to think of any connection between this kind of iceberg (growth) and global warming," said Douglas MacAyeal, a University of Chicago glaciologist who tracks icebergs.

"His research, particularly that with his amazing ability to detect and track icebergs, is really the best method" for determining the actual rate of the creation of icebergs.

Long is careful to distinguish between the birth of large icebergs and the widely publicized collapse of the Larsen B ice shelf last year, which yielded many smaller icebergs.

Other scientists have clearly shown, Long said, that event was the result of localized warming.

Referring to his current study, he said, "This data set is not evidence of global warming. Nor does it refute global warming."

Long and his student assistants have pioneered the use of images generated from the SeaWinds-on-QuikSCAT satellite for tracking icebergs. The NASA satellite carries a device called a scatterometer, which measures the wind speed and direction by recording the reflection of radar beams as they bounce off ocean waves.

Until recently, the resolution of the images generated by the scatterometer was too low to distinguish icebergs. Long's team developed a computer processing technique that produces images sharp enough to reliably track icebergs.

The BYU group has been working with the National Ice Center since 1999, when Long rediscovered a massive iceberg, the size of Rhode Island, threatening Argentine shipping lanes.

The Ice Center had lost track of it because of cloudy skies.

Both Long and MacAyeal said this study does not rule out the possibility that global warming is occurring, or that it could have a future effect on the creation of large icebergs.

"Global warming is real," Long said. "The issues are -- is this strictly man-made or is it part of normal cycles?

There is evidence to support both sides on that one."

Related Links
Brigham Young University
SpaceDaily
Search SpaceDaily
Subscribe To SpaceDaily Express

Giants Joust In The Cold
Antarctica (ESA) Oct 23, 2002
A new giant was born recently in the coastal waters of Antarctica. A series of images captured from May through the beginning of this month by ESA's Envisat satellite shows the subsequent duel between the new iceberg and another as it breaks free of the Ross Ice Shelf and tries to move north.



Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only






Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News








The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.