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Difference between revisions of "Glacier"
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Westarctica (talk | contribs) (Source content drawn from Wikipedia article on glaciers.) |
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[[File:Crevassed-Glacier.jpg|thumb| | [[File:Crevassed-Glacier.jpg|thumb|Heavily crevassed glacier]] | ||
A '''glacier''' (US: /ˈɡleɪʃər/ or UK: /ˈɡlæsiə/) is a persistent body of dense [[ice]] that is constantly moving under its own weight; it forms where the accumulation of snow exceeds its ablation (melting and sublimation) over many years, often centuries. Glaciers slowly deform and flow due to stresses induced by their weight, creating [[crevasse|crevasses]] and other distinguishing features. They also abrade rock and debris from their substrate to create landforms such as cirques and moraines. Glaciers form only on land and are distinct from the much thinner [[sea ice]] and lake ice that form on the surface of bodies of water. | A '''glacier''' (US: /ˈɡleɪʃər/ or UK: /ˈɡlæsiə/) is a persistent body of dense [[ice]] that is constantly moving under its own weight; it forms where the accumulation of snow exceeds its ablation (melting and sublimation) over many years, often centuries. Glaciers slowly deform and flow due to stresses induced by their weight, creating [[crevasse|crevasses]] and other distinguishing features. They also abrade rock and debris from their substrate to create landforms such as cirques and moraines. Glaciers form only on land and are distinct from the much thinner [[sea ice]] and lake ice that form on the surface of bodies of water. | ||
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==Appearance== | ==Appearance== | ||
A large piece of compressed ice, or a glacier, appears blue, as large quantities of water appear blue. This is because water molecules absorb other colors more efficiently than blue. The other reason for the blue color of glaciers is the lack of air bubbles. Air bubbles, which give a white color to ice, are squeezed out by pressure increasing the density of the created ice. | A large piece of compressed [[ice]], or a glacier, appears blue, as large quantities of water appear blue. This is because water molecules absorb other colors more efficiently than blue. The other reason for the blue color of glaciers is the lack of air bubbles. Air bubbles, which give a white color to ice, are squeezed out by pressure increasing the density of the created ice. | ||
==Classification== | ==Classification== | ||
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Mass changes of ice sheets can be monitored by measuring changes in the ice surface height, the deformation of the ground below and the changes in the gravity field over the ice sheet. Thus ICESat, GPS and GRACE satellite mission are useful for such purpose. However, glacial isostatic adjustment of the ice sheets affect ground deformation and the gravity field today. Thus understanding glacial isostatic adjustment is important in monitoring recent global warming. | Mass changes of ice sheets can be monitored by measuring changes in the ice surface height, the deformation of the ground below and the changes in the gravity field over the ice sheet. Thus ICESat, GPS and GRACE satellite mission are useful for such purpose. However, glacial isostatic adjustment of the ice sheets affect ground deformation and the gravity field today. Thus understanding glacial isostatic adjustment is important in monitoring recent global warming. | ||
One of the possible impacts of global warming-triggered rebound may be more volcanic activity in previously ice-capped areas such as Iceland and Greenland. It may also trigger intraplate earthquakes near the [[ice]] margins of Greenland and Antarctica. | One of the possible impacts of global warming-triggered rebound may be more volcanic activity in previously ice-capped areas such as Iceland and Greenland. It may also trigger intraplate earthquakes near the [[ice]] margins of Greenland and [[Antarctica]]. | ||
[[Category:Science]] | [[Category:Science]] | ||