PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA 91109. TELEPHONE (818) 354-5011
Contact: Mary A. Hardin (818) 354-0344
Headquarters, Washington, DC
Goddard Space Flight Center, Greenbelt, MD
Canadian Space Agency, St. Hubert, Quebec
FOR IMMEDIATE RELEASEOctober 1, 1997
RADARSAT BEGINS FIRST COMPLETE DETAILED MAP OF ANTARCTICA
Initial images from the first complete radar survey of
Antarctica, using the Canadian Space Agency's Radarsat mission,
show better-than-expected details of its massive ice streams and
crevices, as well as old, buried features of the international
South Pole research station established in the late 1950s.
"The quality of these first images is quite stunning," said
Dr. Robert Thomas, program manager for polar research in NASA's
Office of Mission to Planet Earth, Washington, DC. "Antarctica
is the only continent on Earth that has not been properly mapped.
Despite many years of research, we still do not know whether this
massive ice sheet is growing larger or smaller. Radarsat should
help us answer this question, and many related questions about
its potential for affecting global sea levels."
Nearly 70 percent of the Earth's fresh water is contained in
the Antarctic region, and changes in this enormous reservoir
directly influence world sea levels and climate. If fully
melted, this ice would raise the global sea level by about 70
meters (230 feet).
Previous research has revealed that about 90 percent of
Antarctic ice flows into the sea via large "ice streams." These
rivers of ice are tens of miles wide and about a half-mile thick,
and can flow rapidly within the predominantly slow-moving ice
sheet. "We know little about why these ice streams form where
they do, or what determines their speed," Thomas said.
"Most Antarctic ice streams flow into 'ice shelves,' large,
floating slabs of ice the size of Texas that rest on the ocean
and occupy most of the Antarctic coastline. They move seaward at
about a half-mile per year, occasionally 'calving' to form huge
Where the seabed beneath an ice shelf becomes sufficiently
shallow, the ice shelf runs aground, slows down and thickens to
form an "ice rise" which tends to slow the seaward progress of
the ice shelf, and ultimately to hinder ice discharge down the
ice streams. If the ice shelf were to become sufficiently thin,
for instance by increased melting from beneath, the speed of ice
discharge would increase, allowing more ice to flow into the
ocean, and thus raising the sea level. "Just how quickly this
could happen if climate were to change is not known, and would
depend heavily on whether the ice sheet is already thinning or,
as some evidence suggests, actually thickening," Thomas said.
"These unknowns are the prime reasons for this research effort."
The first radar image of Earth's geographic South Pole from
the Radarsat Antarctic campaign clearly shows the infrastructure
of the Amunsden-Scott Station operated by the U.S. National
Science Foundation. The image reveals the modern infrastructure
that supports a host of international science programs, but also
shows an abandoned aircraft runway and other remains of the old
South Pole station, now buried under about nine meters (30 feet)
of snow and ice.
This image and several others, as well as further
information on the Radarsat mission, are available on the
Internet at the following URL, under the link to the Antarctic
The Antarctic Mapping Mission was made possible by the
rotation of the Earth-orbiting Radarsat satellite by 180 degrees
from its normal field of view, which was completed on September
11. Full mapping will require the collection of more than 5,000
"Following the successful rotation, 30 percent of the
mission's objectives have now been achieved," said Rolf Mamen,
Director General of Space Operations at the Canadian Space
Agency. "We are extremely pleased with the quality of the radar
images being obtained of this unmapped region of our planet, and
of the contribution we are making to the scientific community."
The high-resolution digital image mosaic of the ice sheet
and exposed portions of the continent to be taken by the
Antarctic Mapping Mission will serve as a benchmark for testing
the predicted effects of global warming on the interior ice sheet and
its bounding ice shelves. This unique data set also will support
the development of policies to help preserve Antarctica in its
relatively pristine state, through the goals subscribed under the
international Antarctic Treaty System.
NASA's Jet Propulsion Laboratory (JPL) is responsible for
coordinating the collection and downlinking of the Antarctic data
through the Alaska Synthetic Aperture Radar Facility (ASF) in
Fairbanks. In addition to JPL and ASF, the U.S. partners in the
Antarctic portion of the Radarsat mission include the Byrd Polar
Research Center of Ohio State University, Columbus, OH; and,
NASA's Goddard Space Flight Center, Greenbelt, MD.
"The job of mapping one of the last largely unexplored
regions of the Earth is truly a mission of international
cooperation, with collaboration that includes scientists from
Great Britain, Germany, Japan, and Australia in addition to the
United States and Canada," said Dr. Kenneth Jezek, a professor of
geological science and director of the Byrd Polar Research Center
at Ohio State University. "In that way, the Antarctic Mapping
Mission is in keeping with the spirit and intent of the Antarctic
treaty, which serves to preserve the continent for peaceful
scientific research by any nation."
In exchange for the launch of the Radarsat satellite by NASA
in November 1995, Canada agreed to provide access to a
proportionate amount of its operational data and to execute the
yaw maneuver of the spacecraft twice during the mission to allow
the mapping of the Antarctic continental ice sheet.
Operated by the Canadian Space Agency from St. Hubert,
Quebec, Radarsat utilizes a sophisticated microwave radar system
able to produce images through cloud cover, smog, haze, smoke,
and darkness. The satellite can be programmed to capture images
of an area as wide as 500 kilometers (800 miles), and it can
detect objects as small as eight meters (26 feet).
NASA's involvement in Radarsat is part of the agency's
Mission to Planet Earth enterprise, a long-term coordinated
research program to study the Earth's land, oceans, air, ice and
life as a total system.