September 16th, 2009 Category: Snapshots

Antarctica - August 23rd, 2009

A large iceberg breaks off the shores of the Antarctic Ice Sheet in Queen Maud Land, or Dronning Maud Land, and floats away in the Southern Ocean. Other smaller icebergs can also be seen floating between the main one and the edge of the ice sheet. Many cracks and rifts are visible in the ice sheet itself.

When a mass of ice suddenly splits off and moves away from its parent glacier, iceberg, or ice shelf in such a way, the event is called calving. Calving of ice shelves is usually preceded by a rift. This ice calving or iceberg calving is a form of ice ablation or ice disruption.

Tags: Antarctic Ice Sheet Antarctica Calving Dronning Maud Land Iceberg Queen Maud Land | Comments (1) |

August 29th, 2009 Category: Snapshots

Antarctica - August 16th, 2009

The seaward side of the Ronne-Filchner ice shelf is divided into Eastern (Filchner) and the larger Western (Ronne) sections by Berkner Island. The whole ice shelf covers some 430,000 km², making it the second largest ice shelf in Antarctica, after the Ross Ice Shelf.

It grows perpetually due to a flow of inland ice sheets. From time to time, when the shearing stresses exceed the strength of the ice, cracks form and large parts of the ice sheet separate from the ice shelf and continue as icebergs. This is known as calving.

In this image, part of the Filchner section along the ocean is visible. A large iceberg can be seen here, with many other smaller icebergs visible nearby, all on the right side of the image.

Tags: Antarctica Ice Icebergs Ronne-Filchner Ice Shelf | Comments (2) |

August 23rd, 2009 Category: Snapshots

Antarctica - June 30th, 2009

This area of Antarctica is found along the coast of the eastern part of the Weddell Sea, which is part of the Southern Ocean. Its land boundaries are defined by the bay formed from the coasts of Coats Land and the Antarctic Peninsula. Much of the southern part of the sea, up to Elephant Island, is permanent ice, the Filchner-Ronne Ice Shelf.

The sea is contained within the two overlapping Antarctic territorial claims of Argentina and Britain, and also resides partially within the territorial claim of Chile. At its widest the sea is around 2,000 km across, in area it is around 2.8 million km².

Tags: Antarctica Ice Southern Ocean Weddell Sea | Comments |

August 20th, 2009 Category: Snapshots

Antarctica - August 16th, 2009

The parallel lines rising up from the flat surface of this part of the West Antarctic Ice Sheet are  phenomena known as ice rises.

These are rounded elevations that form where the ice shelf touches elevated, but nevertheless below sea level, areas in the seabed. The ice shelf flows over the seabed elevation, completely covering it with ice, thereby forming an ice rise. Such ice rises are typically 100 to 200 meters high.

Upon opening the full image, the full length of these ice rises can be observed (bottom), as can cracks along the edge of the ice sheet (top).

Tags: Antarctica Ice Ice Rise West Antarctic Ice Sheet | Comments |