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Posts tagged Glacier

Glacier on West Coast of Greenland

February 1st, 2009 Category: Snapshots

Glacier melting on west coast of Greenland - November 30th, 2008

Glacier melting on west coast of Greenland - November 30th, 2008

Here we can see a large glacier off the western coast of Greenland, seemingly fed by three ice streams.

The largest glaciers are continental glaciers, enormous masses of ice that are not visibly affected by the landscape and that cover the entire surface beneath them, except possibly on the margins where they are thinnest.

Antarctica and Greenland are the only places where continental ice sheets currently exist. These regions contain vast quantities of fresh water.

The volume of ice is so large that if the Greenland ice sheet melted, it would cause sea levels to rise some six meters (20 ft) all around the world.

These ice sheets are further divided into sections based on characteristics. Ice shelves are areas of an ice sheet that are at the margin and are afloat. As a result they are thinner, have limited slopes and reduced velocities.

Ice streams, like the three visible in the image, are fast moving sections of an ice sheet.

source Wikipedia

Antarctic Landscape

January 15th, 2009 Category: Snapshots

Ice stream and glacier, Antarctica - January 13th, 2009

Ice stream and glacier, Antarctica - January 13th, 2009

Diverse land features in West Antarctica can be seen here:  a glacier (bottom right)  is nestled among a mountain range (bottom) as an ice stream flows past (top).

By clicking on the thumbnail to open the full image, more of the ice stream can be seen.  To the North, two ice streams join together.

Melting Glacier in Greenland

January 12th, 2009 Category: Snapshots

Melting glacier in Greenland - November 30th, 2008

Melting glacier in Greenland - November 30th, 2008

A glacier gradually melts into the Arctic Ocean off the coast of Greenland.

Glaciers form where snow and ice accumulation exceed snow and ice melt. As the snow and ice thicken it will reach a point where it begins to move.

The snow that forms glaciers is subject to repeated freezing and thawing, which changes it into a form of granular ice called firn. Under the pressure of the layers of ice and snow above it, this granular ice fuses into denser and denser firn.

Over a period of years, layers of firn undergo further compaction and become glacial ice, seen on the right hand side of the image.

On the opposite end of the glacier, at its foot or terminal, is the deposition or ablation zone, where more ice is lost through melting than gained from snowfall and sediment is deposited. This zone can be seen towards the left, as chunks of ice breaking off the more solid part of the glacier.

The place where the glacier thins to nothing is called the ice front, visible on the far left of the image.

source Wikipedia

Glaciers and Ice Streams in Antarctica – December 19th, 2008

December 19th, 2008 Category: Image of the day

Glaciers in Antartica - December 13th, 2008

Glaciers in Antartica - December 13th, 2008

Close-up of two glaciers

Close-up of two glaciers

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.

Close-up of ice sheet

Close-up of ice sheet

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.

source Wikipedia