Glaciers and Ice Streams in Antarctica – December 19th, 2008
This ASAR (radar) image gives a fine view of the contours of two glaciers and an ice sheet in Antartica.
A glacier is a large, slow-moving mass of ice, formed from compacted layers of snow, that slowly deforms and flows in response to gravity and high pressure.
Both glaciers in the image appear bright white as much light reflects off their icy slopes. The darker grey lines show the movement of the melting ice.
Upon opening the second close-up image, ice streams appear as lines in an ice shelf or ice sheet. An ice stream is a region of an ice sheet that moves significantly faster than the surrounding ice.
Ice streams are significant features of the Antarctic where they account for 10% of the volume of the ice. They are up to 50 km wide and 2 km thick. They stretch for hundreds of kilometres and account for most of the ice leaving the ice sheet and entering the ice shelf.