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. 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. 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.
Reds indicate areas of greatest speed, while greens and blues are slower.
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. 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. It's huge, too-the size of the United States and Mexico combined.