MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
Contact: Diane Ainsworth
FOR IMMEDIATE RELEASE
September 3, 1999
NEW NASA OCEAN RADAR WATCHES FOR BREAKUP OF GIANT ICEBERG
A NASA satellite instrument is
keeping an eye on an iceberg the size of Rhode Island, the first time
this space technology has been used to track a potential threat to
NASA's new orbiting SeaWinds
radar instrument, flying aboard the QuikScat satellite, will monitor
Iceberg B10A, which snapped off Antarctica seven years ago and has
since drifted into a shipping lane.
Iceberg B10A, which measures
about 38 by 77 kilometers (about 24 miles by 48 miles), was spotted
by the Instrument during its first pass over Antarctica, demonstrating
SeaWinds' all-weather and day-night observational capabilities. The
massive iceberg extends about 90 meters (300 feet) above water and
may reach as deep as 300 meters (1,000 feet) below the ocean's surface.
It is breaking up into smaller pieces that could pose a threat to
commercial, cruise and fishing ships if the pieces are blown back
into the shipping lane by high winds.
"Although the iceberg isn't posing
a threat to ships in the area right now, pieces of B10A could be blown
back into the shipping lane and become a danger to ships using the
Antarctic's Drake Passage," said Dr. David Long, a member of the SeaWinds
science team from Utah's Brigham Young University, Provo, UT. Long
said that the SeaWinds instrument will be able to help scientists
at the National Ice Center, Suitland, MD, track pieces of the iceberg
down to 4 kilometers (about 2.5 miles) in size.
B10A, which took hundreds of
thousands of years to form, broke off the end of the Thwaites glacier
of Antarctica in 1992 and has been drifting in the ocean ever since,
driven by ocean currents and wind. In 1995, the iceberg broke in half,
but was being tracked on a regular basis. Although conventional methods
of tracking sea-surface ice -- using ships' radar, shipping reports,
optical images from satellites and microwave sensor data -- are usually
sufficient for tracking large pieces of ice, icebergs can sometimes
disappear in the poor visibility of dark, cloudy Antarctic winters.
"That happened earlier this year,
when we lost track of B10A's exact whereabouts," Long said. "Even
though a ship was dispatched to the iceberg's last known position,
we were unable to find it until we started receiving data from the
SeaWinds instrument in July."
Scientists were surprised at
its location when they found B10A, but it was clearly identified as
a very large iceberg that posed a considerable threat to ships in
the area. A check with the Naval Ice Center confirmed the iceberg's
identity and has enabled scientists to continue tracking its journey
through the Drake Passage. When it was rediscovered earlier this month
heading northeast between Tierra del Fuego at the southern tip of
South America and the Antarctic Peninsula, the National Ice Center
issued an iceberg navigation warning to the Argentine government.
Ironically, the iceberg that
took many millennia to form is expected to break up within about three
months because it is drifting into warmer waters, Long said. "We will
be able to watch the iceberg's breakup for the first time with daily
radar observations and better understand the effects of ocean winds
and climate on melting polar ice," Long said. "The polar regions play
a central role in regulating global climate, and it is important to
accurately record and monitor the extent and surface conditions of
Earth's major ice masses."
More information about the SeaWinds
mission and observations is available at the following URLs:
The orbiting SeaWinds radar instrument,
launched on the QuikScat satellite on June 19, is managed for NASA's
Office of Earth Science, Washington, DC, by NASA's Jet Propulsion
Laboratory, Pasadena, CA. JPL also built the SeaWinds radar instrument
and is providing ground science processing systems. NASA's Goddard
Space Flight Center, Greenbelt, MD, managed development of the satellite,
designed and built by Ball Aerospace & Technologies Corp., Boulder,
CO. The National Oceanic and Atmospheric Administration has contributed
support to ground systems processing and related activities.
NASA's Earth Science Enterprise
is a long-term research and technology program designed to examine
Earth's land, oceans, atmosphere, ice and life as a total integrated
JPL is a division of the California
Institute of Technology, Pasadena, CA.