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Snow and ice are pervasive elements of high latitude environmental systems and have an active role in the global environment. Glaciologists in Antarctica are concerned with the study of the history and dynamics of all naturally occurring forms of snow and ice, including floating ice, seasonal snow, glaciers, and continental and marine ice sheets.
One priority for scientists is to determine the origins of the polar ice sheet, along with the fundamental behavior of the ice sheet during worldwide glaciations.
- Antarctic ice has accumulated over millions of years.
- The ice is up to 3 miles deep and covers about 5.3 million square miles, or about 97.6 percent of the continent.
- This volume of ice amounts to about 6 million cubic miles - if it were returned to the oceans, it would raise global sea level about 200 feet.
- The average thickness of ice makes Antarctica the highest continent.
- Antarctic ice represents 90 percent of all the world's ice and 70 percent of all the world's fresh water.
Data has shown that the East Antarctic ice sheet has remained relatively static during worldwide glaciation whereas the marine-based West Antarctic Ice sheet has expanded to the eastern edges of the Ross and Weddell continental shelves, nearly tripling in size in the process.
Of critical importance to glaciological research is the examination of deep ice cores. Ice cores are unique in that they continuously record and preserve annual precipitation, atmospheric temperature and components of the atmosphere, including gases, soluble and insoluble aerosol particles from a wide variety of sources.
Another focus for scientists is to improve our understanding of the growth and movement of Antarctic sea ice, not only to aid in navigation but to give insight into future changes. Sea ice originates on or at the edge of the polar land mass and is dispersed by strong winds blowing northward into the surrounding oceans. Annually the ice pack grows from an average minimum of 2.9 million square kilometers in March to about 18.8 square kilometers in September. The average thickness of the sea ice is about 1.5 meters and 85 percent of the ice pack melts each year. This ice is characterized by undulating ridges and troughs and crevassed areas which have created route-finding problems for those traveling across these marginal areas of the ice shelf. The pack moves quickly with the winds--as much as 65 kilometers in a single day--and ships can easily be caught in some of the thicker, more complex multiyear ice that is trapped within indentations on the Ross Sea coastline.
- About one-third of the Antarctic coastline is comprised of ice shelves-floating ice fed by glaciers emanating from the vast polar plateau and by snowfall upon their surfaces.
- The ice shelves are as much as 300 meters thick at their seaward edges and they thicken toward the land.
- Ross Ice Shelf is the largest, covering about 520,000 square kilometers and measuring about 650 kilometers across.
- It moves northward to the Ross Sea, flowing about 1.4 kilometers a year, where it calves tabular icebergs, some small and some covering more than 200 square kilometers or more.
- Glaciologists monitor not only when a giant berg breaks off one of Antarctica's ice shelves, but also measure its slow progress away from the continent.
- Other research on the ice shelves concentrates on determining flow rates to see how quickly ice is moving off the continent, and how rapidly the shelf ice thins from the melting of its underside.
- The long-term objective is to provide researchers with a computer model that will allow the loss of ice to the Southern Ocean to be accurately predicted..
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