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Antarctica mapped with RADARSAT data

On this web site you'll find text, visualizations, pictures, and links relating an exciting research project studying Antarctica.

Images of the Entire Antarctica Continent Mapped with RADARSAT

For 18 days during the Southern Hemisphere spring of 1997, a NASA-launched Canadian satellite called RADARSAT collected pieces of a puzzle that will help scientists study the most remote and inaccessible part of the Earth -- Antarctica. Scientists now have the puzzle pieces put together, forming the first high-resolution radar map of the mysterious frozen continent. With detail to the point of picking out a research bungalow on an iceberg, the new map has both answered scientists' questions about the icy continent, and left them scratching their heads about what to make of strange and fascinating features never seen before.

Read the official press release about the RADARSAT Mapping Mission


Just like radar sweeping the sky looking for airplanes, RADARSAT paints the Earth, reading the surface. But instead of a momentary radar "ping", RADARSAT collects radar data from across a swath it's observing. That data can then be used to construct a map of a particular region, a map derived from readings of radar reflectivity.

Unlike traditional photographs from space, a dark area does not necessarily mean that less light is falling on the surface; as translated by radar, dark does not mean shadow. Instead, light and dark are relative measurements of radar reflectivity. Finely powdered snow and smooth ice with few imperfections both tend not to scatter radar projected against it; hence they look dark. Coarse material like old, pitted ice, rock slides, and crevasses scatter the radar beam and thus look bright--a strong radar signal. When the images are put together, they appear to form a map with shadows and hot spots, but in fact the light areas mean there's a strong radar reflection while the dark areas mean there's little to reflect the radar beam.

RADARSAT is the optimal instrument for high resolution imaging of Antarctica for three important reasons. RADARSAT carries its own source of illumination, in this case radar. Therefore it can operate day or night, and at the poles night stretches on for months. Moreover, radar can penetrate clouds, highly pervasive over much of Antarctica. RADARSAT is also unusual in that it can rotate in orbit, changing its imaging perspective in a way that's different from any other radar satellite. This ability to be reoriented in space is what allowed researchers to collect images of the continent at the bottom of the Earth.


Antarctica the coldest, windiest, driest, and on average highest continent on Earth. It's huge, too-the size of the United States and Mexico combined. While over 97 percent of the continent is ice covered, its surface is remarkably diverse. Glaciers plow through 15,000 ft. mountain ranges, rising above the land like citadel spires. Fields of crazed ice stretch out as far as the eye can see. Icebergs the size of New England States calve from walls of floating ice that are themselves as big as Texas.

By stitching together the RADARSAT data, scientists at Ohio State University's Byrd Polar Research Center and animators at NASA's Goddard Space Flight Center have designed a virtual tour of the southernmost continent. It begins and ends at McMurdo Station; in between are thousands of miles of mystery and beauty.

Points of interest in this virtual tour include the following:


Ross Island and the McMurdo Tracking Station

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Ross Island is home to McMurdo Station, the largest permanent facility on the continent. Owned by the United States, McMurdo Station and its attendant airport called Williams Field are primary gateways to the rest of the frozen territory of Antarctica. Nearly 1200 researchers and support staff live at McMurdo during the summer months; about 230 remain year round.

The high point of Ross Island is Mt. Erebus, rising 3794 meters. It's also the most active volcano on the continent and one of the active volcanic vents that's responsible for the formation of the island. Many days of the year a plume can be seen emanating from the mountain's summit crater, which holds a unique lava lake. The mountain is essentially active all the time, producing small explosions from the lava lake several to many hundreds of times per day.


McMurdo Dry Valleys

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These valleys found at the eastern edge of the Transantarctic Mountains are essentially snow free. Melt water from alpine glaciers essentially run into these valleys and feed a number of lakes and small ponds, but otherwise, it gets very little moisture. It is a delicate environment. But its relative protection from the harsher surrounding features of the mountains and East Antarctic Ice Sheet also provides a unique opportunity for intense study. The National Science Foundation maintains a long term ecological research site in the McMurdo Dry Valleys to study the area and ecosystem.

The area is also something of a practice facility. The cold, arid conditions provide a fairly good simulation of the surface of Mars. NASA engineers have used the Dry Valleys to test equipment and operational techniques in preparation for a chance to try their designs on the Red Planet.


Allen Hills

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Along the edge of the Transantarctic Mountains lay the Allen Hills. Ice pushes up against the slopes of the hills, nudging bits of debris and surface material along. There against the slopes that ice ablates rather quickly-it's worn away-by wind and solar insolation. Left behind, however, are the geological artifacts that most interest scientists, including fragments from 3 meteorites. It is from the Allen Hills that several years ago scientists found several fragments of something they believe is an actual piece of Earth's second closest neighbor: Mars.


South Pole

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The U.S. National Science Foundation (NSF) operates the Amundsen-Scott South Pole Station, but it's been a way station for researchers from around the world. Seen from RADARSAT, the main geodesic dome is visible along with several storage facilities. Extending to the upper right from the research station is a long line. It's a highway of sorts, heading to a now abandoned antenna facility. The bright band below the main station is the airfield for the facility 14,000 feet long.

South pole station is important to RADARSAT researchers in that it provides a vital point of cartographic reference in every pass the craft makes over the continent.



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Prior to the RADARSAT mission, scientists knew little about these ice streams which drain into the Filchner Ice Shelf. Now, for the first time they've been mapped in their entirety. They're actually enormous glaciers, stretching like conveyors of cracked ice and snow across vast stretches of the continent. The Recovery Glacier, one of the principal channels comprising the East Antarctic Ice Streams, reaches over 800 kilometers into the continent's interior. Several of the tributary glaciers feeding into Recovery themselves extend for more than 250 kilometers.

The West Antarctic Ice Streams are to Antarctica what a fast eddy is to an already dynamic river. Moving roughly 500 meters a year--significantly faster than a typical glacier--the ice streams are hundreds of kilometers long and up to fifty kilometers wide. By comparison, the frozen material lining these remarkable rivers may move only a couple of dozen meters a year.

RADARSAT is an excellent tool for scientists to study these fascinating formations. If you were standing on the gently sloping ground they'd be very hard to detect. From space, however, the West Antarctic Ice Streams show up as clear as a river seen from a plane. Experts are still not positive about why they move so quickly; unlike water rushing down a trough there isn't much of a slope to pull them. Theories include a lubricated stream bed of some sort, helping the ice rush across the frozen continent like waxed sled runners in a groove.



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RADARSAT provides a unique view of an unusual surface feature striping the continent. Dunes of snow more than 10 kilometers long stretch out across east and west Antarctica. Unlike their sand analogues in more familiar deserts around the globe, these dunes tend not to rise nearly as high. Their length and relative heights raise interesting questions for researchers. One hypothesis about their formation suggests that low intensity atmospheric waves formed in the lee of small hills help cause the dunes, but so far conclusive answers are elusive.

RADARSAT "sees" the ridges of the dunes not by traditional shadows, but by the way the radar signal is reflected back to the satellite. Because wind sorts flakes of snow according to size on the up-wind and down-wind sides of hills, RADARSAT's view of the area looks to be measuring height, when in fact it's measuring radar reflectivity. That reflectivity helps scientists determine what types of materials line the sides of the dunes, and thus help them determine how they came to develop.


Lake Vostok

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More than two miles beneath the icy cloak shielding Antarctica from the sky hides a massive fresh water lake. Seen from RADARSAT, the lake appears as a flat plain surrounded by the sandpaper of craggy ice. As the topographical ice sheet flows over the subglacial lake, surface features smooth out. Researchers are considering a drilling mission to the lake for exploration of this remote environment. It remains in liquid state partially due to geothermal heating and partially because of the insulating properties of such a thick ice blanket above. Assuming financial issues can be resolved, the drilling project faces certain technological challenges, too. Major mechanical work is always a challenge in the bitter cold. But from a more research oriented perspective, there's the issue of how to drill into the lake from above without contaminating a sample from below with the drilling apparatus.

Lake Vostok is also a human foothold on the continent. Due to concerns about continued funding, the future of the Russian outpost located at the southern edge of the lake is in question. Note the long, lonely road leading across the ice to the outpost at Vostok. At the end of the road, the short, white dash in the ice marks the station's airport runway.


Larsen Ice Shelf

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In 1978, scientists predicted that global warming would lead to a disintegration of Antarctic Peninsula ice shelves. Spaceborne data indicate that this prediction may be coming true. In these before and after images, note the dramatic change in the apparent shoreline. Scientists captured the first image in using the ERS-1 satellite in 1992. As seen in the second image, collected by RADARSAT in 1997, huge changes have come to the coastline. In 1995, a 2000 sq. kilometer section of the ice shelf collapsed into thousands of fragments that eventually drifted out to sea. Researchers are still debating why the ice shelf broke up so dramatically, and what significance the break up has for interpreting local versus global changes to the environment. Theories include a series of warmer than usual summers which may have caused high levels of surface melting, or an overall climate warming trend.


Fimbul Ice Shelf

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Icebergs form when hunks of ice break away from glaciers pushing into the ocean. Ice shelves are the edges of those glaciers, extending out into the ocean faster than ice bergs can break off from the edge. The Fimbul Ice Shelf has remained relatively consistent in its appearance for the last thirty years, but researchers are paying close attention to changes. Ice shelves are considered to be particularly sensitive to climatic changes and scientists have detected a marked retreat of several along the Antarctic Peninsula.

Note the fascinating formations along the Fimbul, believed to be the product of glacial ice flowing over rocky outcroppings and islands.


Lambert Glacier Lambert Glacier 2
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Covering more than a million square kilometers, Lambert Glacier is one of the world's longest and largest. It's more than 400 kilometers long, emptying a significant portion of East Antarctica into the Amery Ice Shelf. Much like a major river system, Lambert Glacier is fed by a complex series of tributaries.


Lambert Glacier

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At the mouth of the Lambert Glacier spreads the Amery Ice Shelf. For the most part, ice shelves grow from glaciers pushing down into the sea. To a lesser extent they also grow from precipitation. Ice Shelves respond to climate change faster than sheets of ice on the ground or continental glaciers. Continued study of ice shelves like Amery are intended to help scientists better understand what sorts of changes are happening to the world's climate in general. Of particular interest is whether observed changes in various ice shelves are the result of natural processes or are anthropogenic, that is, the result of actions taken by humans.


Ronne Ice Shelf

The Ronne Ice Shelf grows primarily due to a constant flow from inland ice sheets. Where shearing stresses are greater than the strength of the ice itself, cracks form. These cracks ultimately widen and spread like varicose veins in the frozen skin of the coast, only to break loose and become icebergs. Early in the 1990's a slab of ice the size of Delaware broke free from this area. A recent iceberg more than 40 miles wide now floating in the South Atlantic originated from the Ronne Ice Shelf.

Interestingly, as ice shelves break up into ice bergs, the sea level generally doesn't rise. That's because ice shelf are ostensibly already floating in the water. That floating ice, connected to the shore by ice sheets and glaciers, displaces a volume of water equal to the volume of water contained in the shelf. When a berg breaks off, or calves, there is no new water to displace. It simply separates from shore...and goes on its way.



Belgica QuickTimes

In 1899, the not yet famous polar explorer Roald Amundsen served aboard the Belgian ship Belgica as it sailed around the edge of the southernmost continent. Under the command of an ambitious 29 year old Belgian Navy Lieutenant Adrien Victor Joseph de Gerlache, the voyage that began as one of discovery and adventure became a test of endurance and will.

Trapped for nearly 13 months in shifting pack ice seven feet thick, most of the Belgica crew weathered isolation, limited food and fuel, and endless, grinding cold before finding their way free to open water. On the map note how the shifting ice dragged ship around the edge of the continent while they were trapped.


Race to the Pole QuickTimes RADARSAT data
Race to the Pole QuickTimes

In the winter of 1911 and 1912, two teams of explorers raced to reach the South Pole. Of the two five-man teams, only one group managed to return alive from the destination.

Norweigan explorer Roald Amundsen led his crew with teams of dog pulling sleds across the bare ice. They planted a flag at the bottom of the world on December 14th, 1911. On January 16th, 1912 a British team led by Robert Falcon Scott, travelling under their own power, reached the pole. Beset by frostbite, logistical miscalculations, and several navigational mistakes, the team died before they made it back to shore. Scott himself died a mere handful of miles from his base camp. Months later another expedition to Antarctica found Scott's detailed diary in his tent.


Byrd Flies over the South Pole

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On November 29, 1929, Navy pilot and at that time Commander Richard Evelyn Byrd and a crew of two made the first flight over the south pole. He did it in a three engine Ford airplane called the Floyd Bennett. Byrd used the trip to drop supplies to several geological expeditions making their way across the ice below, but the eighteen hour, forty-one minute journey's clear focus was an over-flight of the South Pole. In fact, with Byrd acting as navigator, the three men made several sweeping passes over the general area around the pole, just to be sure they could actually claim they had successfully reached their goal.


NASA launched the RADARSAT satellite for the Canadian Space Agency in exchange for certain operational executions. Unlike mapping satellites that rely on reflected sunlight or infrared readings, RADARSAT's Synthetic Aperture Radar (SAR) is able to penetrate cloud cover or work in the dark of night.

RADARSAT Spacecraft Movie

RADARSAT Spacecraft Movie


This project is the collaborative result of many organizations, agencies, corporations, and countless individuals. Below you'll find links to many sites of groups that played a role in making this project a reality.

Credit line for all images:
NASA/Goddard Space Flight Center - Scientific Visualization Studio
Canadian Space Agency
RADARSAT International Inc.

NOTE: All RADARSAT images presented on this website are for research and educational use only. All commercial use of RADARSAT data must be coordinated with the Canadian Space Agency.