1999 EARTH SCIENCE VIDEOTAPES |
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Tape Title | Record ID | Date Produced | TRT: |
Synopsis |
| RADARSAT MAPS SLOW MOTION WHITE WATER RIVERS | G99-099 | 12/13/99 | 00:20:47 | Recent observations by a NASA-launched Canadian spacecraft called RADARSAT are giving scientists a remarkable view of two fascinating features of Antarctica's landscape. Over a twenty-four day period, the satellite captured new images of the frozen continent, providing dramatic new data sets for researchers to consider. NASA's study of Antarctica is part of the Agency's Earth Science Enterprise, a dedicated effort to better understand how natural and human-induced changes affect our Earth's environmental system.
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TAPE CONTENTS: |
| ITEM (1): LOCATING THE STREAMS ON THE CONTINENT - Over a twenty-four day span, scientists used two images over identical regions of Antarctica in a technique called interferomtry. Their comparative analysis of the images helped develop the following ice stream animations on the west side of the continent, showing flow rate and direction to an extent never before possible. Courtesy: NASA
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| ITEM (2): VECTOR ANALYSIS OF FLOW - In this visualization, longer black lines indicate a faster rate of flow than shorter lines. The fastest ice streams can move 400 to 500 meters a year, a blazing speed compared to tributary speeds of little more than 10 meters a year. Experts say the new information can help decribe large scale changes to the Antarctic environment, as well as historical models about geological change. Courtesy: NASA
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| ITEM (3): FALSE COLOR ILLUSTRATION OF FLOW - False color data derived from the RADARSAT interferometry helps illustrate the areas of the streams moving at different rates. Reds indicate areas of greatest speed, while greens and blues are slower. Courtesy: NASA
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| ITEM (4): SNOWDUNES - RADARSAT also enabled researchers to gain a better understanding about a surface feature found only at the bottom of the world. These snow dunes are believed to be highly stable waves of graded ice grains, nearly impossible to see without the aid of satellite remote sensing systems, and larger than the state of California. Stretching for hundreds of kilometers, these dunes rise only 2 to 3 meters but may have a periodicity of more than 2 kilometers. Courtesy: NASA
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| ITEM (5): A VIRTUAL MODEL OF THE ICE STREAMS - Experts still aren't positive how ice streams actually work. The current theory says that tributaries of slower ice come together to create larger streams, often at points where elevation and terrain act as a slight funnel. The convergence then literally slides on a lubricated bed of oceanic muck covered by a millimeter thin layer of water, gaining strength as it drives toward the sea. Courtesy: NASA
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| ITEM (6): SELECTED SOUNDBITES W/ ROBERT BINDSCHADLER, GLACIOLOGIST
Courtesy: NASA
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| ITEM (7): SELECTED SOUNDBITES W/MARK FAHNESTOCK, GLACIOLOGIST, UNIVERSITY OF MARYLAND
Courtesy: NASA
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| ITEM (8): CONTINENTtAL TOUR - Antarctica is 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 remarkable diverse. Glaciers plow through 15,000 ft. mountain ranges, rising above the land like citadel spires. Fields of 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. Courtesy: NASA
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| ITEM (9): FIMBUL ICE SHELF - 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. Courtesy: NASA
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| ITEM (10): LAKE VOSTOK - 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. The drilling project faces certain technological challenges. Lake Vostok is also a human foothold on the continent. It was at Vostok Station, located at the southern end of the lake, that Russian scientists recorded the coldest temperatures on Earth. 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. Courtesy: NASA
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| ITEM (11): LAMBERT GLACIER - 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. Courtesy: NASA
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| ITEM (12): EAST ANTARCTIC ICE STREAMS - Prior to the RADARSAT mission, scientists knew little about the East Antarctic Ice Streams, draining 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 and the large Slessor Glacier extend for more than 250 kilometers. Courtesy: NASA
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| ITEM (13): THE RADARSAT SATELLITE - 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. Courtesy: NASA
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