From: Canadian Space Agency
Posted: Wednesday, March 21, 2001
Saint-Hubert, March 21, 2001- Images produced by RADARSAT-1, Canada's renowned Earth Observation satellite is helping a team of scientists answer crucial questions about the rate and extent of global climate change in Antarctica. This initiative, the second since 1997, was a joint project of the Canadian Space Agency and NASA.
Early analyses show that in just three years the Amery Ice Shelf has advanced five kilometres, while the Shirase Glacier, located in the Indian Ocean sector of the continent, has retreated twelve kilometres. Scientists are seeking to understand whether this variability is due to the forces of external climate on the great ice sheet or due to natural and episodic instabilities that arise from the forces that control complex glacier flow. The new velocity measurements from this second completed mission will help answer these questions.
"The Antarctic Ice Sheet moves slowly and surely under the force of its own enormous weight," says Principal Scientist Dr. Kenneth C. Jezek of The Ohio State University's Byrd Polar Research Center. "This mission gives us the first, overall snapshot of how the ice moves and important new insight into how and why the ice sheet is changing. Moreover, by measuring the extent and velocity of the moving ice and estimating its thickness, we can estimate how much ice may be lost into the ocean from Earth's largest storehouse of freshwater. These calculations are important for understanding Antarctica's contribution to the present rate of sea level rise of about two millimeters a year."
For this mission, the Canadian Space Agency's RADARSAT-1 satellite trained its imaging radar on the outer half of the continent twice during each of three consecutive 24-day periods, ending last Nov. 14. "This was a challenging mission for our professionals who had to accurately navigate the satellite, controlling the 800 kilometre orbit, while periodically firing the spacecraft's onboard thrusters so as to position the satellite within a few hundred meters of its nominal track on each orbit," said Rolf Mamen, Director General of Space Operations at the Canadian Space Agency. Precise navigation and data from the six passes make it possible to create detailed topographic maps and to measure the speed of the moving glaciers.
The two scientific missions supported by RADARSAT-1 have produced a new baseline dataset for the scientific community-one that will prove invaluable in monitoring the state of the Antarctic ice cap. And although RADARSAT-1 is being exploited by the Canadian Space Agency beyond its nominal lifetime, this same leading-edge technology continues to produce outstanding imagery is also being brought to bear on studies of polar ice in Canada's Arctic region.
RADARSAT-2, currently under construction for the Canadian Space Agency by MacDonald Dettwiler and Associates of British Columbia and scheduled for launch in 2003, will contribute to expanding the vast data archive already captured by RADARSAT-1. These unique Earth Observation spacecraft, and the team of highly skilled Canadian Space Agency professionals operating them, are performing an important service, providing key data for clients in the fields of mapping, geology, oceanography, ice surveillance, agriculture, natural resources exploration, supporting disaster and relief efforts worldwide and helping scientists improve their understanding and measure the effects of global warming on our planet Earth.
About the Antarctic Mapping Missions
Building on the success of the first complete mapping of the continent in 1997, RADARSAT-1 was again deployed in November, 2000 to support a second Antarctic Mapping Mission. This follow-on initiative was a joint project of the Canadian Space Agency and NASA. The science team includes members from the Byrd Polar Research Center at The Ohio State University, NASA's Jet Propulsion Laboratory, the Alaska SAR Facility at the University of Alaska, Fairbanks, and the Vexcel Corporation. The mission is part of NASA's Earth Science Enterprise, a long-term research program dedicated to studying how human-induced and natural changes affect our global environment. About the Canadian Space Agency
Established in 1989 and situated in Saint-Hubert, Quebec, the Canadian Space Agency (CSA) coordinates all aspects of the Canadian Space Program. Through its Space Knowledge, Applications and Industry Development business line, the CSA delivers services involving: Earth and the Environment; Space Science; Human Presence in Space; Satellite Communications; Generic Space Technologies; Space Qualification Services and Awareness. The Canadian Space Agency is at the forefront of the development and application of space knowledge for the benefit of Canadians and humanity.
For more information:
B-Roll will be broadcast on NASA TV, March 22 between 16:30-21:00 (GE-2., transponder 9C, C-Band, 85 degrees West longitude; frequency 3888.0 MHz, polarization vertical, audio monaural at 6.8 MHz)
The mission: http://www-bprc.mps.ohio-state.edu/radarsat
The images: http://www.jpl.nasa.gov/pictures/antarctica/
The Canadian Space Agency and RADARSAT-1: http://www.space.gc.ca
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Senior Communications Advisor
Canadian Space Agency
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