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Posts tagged Glacier

Early Summer Melting Affecting Fuchs Ice Piedmont, Adelaide Island, Antarctica – January 7th, 2013

67.1S 68.1W

January 7th, 2013 Category: Climate Change, Glaciers and Ice Caps, Image of the day

Antarctica – January 6th, 2013

Small icebergs can be seen breaking off the coast of Antarctica, near Adelaide Island (upper right quadrant). Adelaide Island, also known as  Isla Adelaida and Isla Belgrano, is a large, mainly ice-covered island, 75 miles (121 km) long and 20 miles (32 km) wide, lying at the north side of Marguerite Bay off the west coast of the Antarctic Peninsula. The Ginger Islands lie off the southern end.

Located on Adelaide Island is the Fuchs Ice Piedmont, an ice piedmont (ice covering a coastal strip of low-lying land backed by mountains) that is 70 nautical miles (130 km) long, extending in a northeast–southwest direction along the entire west coast of the island. According to Chilean scientists, the snow-covered surface of the glacier has progressively deteriorated over the years, due to increasingly early summer melting. Crevasses appear on the glacier surface progressively earlier in the summer, presumably due to higher snowmelt and perhaps higher ice velocities, in response to regional atmospheric warming.

Glaciers and Ice Rises in Antarctica

78S 33.7W

August 6th, 2009 Category: Snapshots

Antarctica - June 30th, 2009

Antarctica - June 30th, 2009

Both glaciers (upper right) and ice rises (lower right) can be observed in this view of Antarctica between the Ronne Ice Shelf and Queen Maud Land. A glacier is a large mass of ice moving slowly over some land surface or down a valley, formed over long periods from the accumulation of snow in areas where the amount of snow that falls exceeds the amount that melts.

While glaciers can be found on all continents except Australia, ice rises are found only on the ice shelves of Antarctica, mostly on the Ronne Ice Shelf. The largest ice rises exceed dimensions of 50 by 200 km, or 10 000 km² in area.

An ice rise is a clearly defined elevation of the otherwise totally flat ice shelf, typically dome-shaped and rising 100 to 200 meters above the surrounding ice shelf. An ice rise forms where the ice shelf touches the rocky seabed because of an elevation that does not reach sea level.

The ice shelf flows over this obstacle, which is completely covered by ice, with no rock exposed, thereby forming an ice rise. The resulting tension forms crevasses around the ice rise. Although ice rises are typically located within the ice shelf area, they can partially face the open sea.

Vatnajökull Glacier and Öskjuvatn Lake, Iceland

July 4th, 2009 Category: Lakes

Iceland - July 1st, 2009

Iceland - July 1st, 2009

This orthorectified ASAR (radar) image extends from the highlands of Iceland to a large, glacier-covered area. In the full image, the country’s steep southeastern coastline and ocean are also visible.

The smooth, dark grey area in the lower left quadrant is part of the Vatnajökull, the largest glacier in Iceland. It is located in the south-east of the island, covering more than 8% of the country. With a size of 8,100 km², it is the largest glacier in Europe in volume (3,100 km³) and the second largest in area.

North of the glacier, in the upper left quadrant, is a rounded form with a surface area of about 11 km²; this is the lake Öskjuvatn. With a depth of 220 m, it is the deepest lake in Iceland. The lake is situated in the crater of the volcano Askja. Like the neighbouring crater Víti, it was created by an enormous volcanic eruption in 1875.

Melting Glaciers in Antarctica

April 30th, 2009 Category: Climate Change

Fires in Nepal - April 24th, 2009

Fires in Nepal - April 24th, 2009

Close-up

Close-up

In the full image, glaciers and ice streams can be seen south of the Kemp Peninsula, in Palmer Land on the eastern coast of the Antarctica Peninsula. The close-up shows icebergs breaking off the glacier.

Glaciers in Antarctica are melting faster and across a much wider area than previously thought, scientists say, a development that threatens to raise sea levels worldwide and force millions of people to flee low-lying areas, reports USA Today.

Researchers once believed that the melting was limited to areas like the one visible here on the Antarctic Peninsula, a narrow tongue of land pointing toward South America. However, satellite data and automated weather stations now indicate it is more widespread, even extending all the way down to west Antarctica near the South Pole.

By the end of the century, the accelerated melting could cause sea levels to climb by 3 to 5 feet — levels substantially higher than predicted by a major scientific group just two years ago.

Making matters worse, scientists said, ice shelves, such as the Wilkins Ice Shelf, that hold the glaciers back from the sea are also weakening.

The biggest of the western glaciers, the Pine Island Glacier, is moving 40% faster than it was in the 1970s, discharging water and ice more rapidly into the ocean. The Smith Glacier, also in west Antarctica, is moving 83% faster than in 1992.

The glaciers are slipping into the sea faster because the floating ice shelf that would normally stop them, which is usually 650 to 980 feet thick, is melting. Together, all the glaciers in west Antarctica are losing a total of around 114 billion tons per year because the melting is much greater than the new snowfall.

The glaciers’ discharge is making a significant contribution to increasing sea levels. Some people fear that this is the first signs of a collapse of the west Antarctic ice sheet, which would cause a sea level rise of between 1 and 1.5 meters (about 3.5 to 5 feet).

Mount Aniakchak and Mount Veniaminof, Alaska – February 20th, 2009

February 20th, 2009 Category: Image of the day, Volcanoes

Alaska - February 17th, 2009

Alaska - February 17th, 2009

Two snow-covered volcanoes, Mount Aniakchak and Mount Veniaminof, are located in the Aleutian Rangeon on this Alaskan peninsula, USA, between the Bering Sea (left) and the Gulf of Alaska (right).

Mount Aniakchak, visible just north of the image center, is a 3,400 year old volcanic caldera (about 10 kilometres [6 mi] in diameter).

It is an extant volcano – at least ten lava flows have occurred since the formation of the caldera; the most recent was in 1931.

Surprise Lake, within the caldera, is the source of the Aniakchak River, a National Wild River. The area around the volcano is the Aniakchak National Monument and Preserve.

To the southwest, Mount Veniaminof is an active stratovolcano located on the Alaska Peninsula. The Alaska Volcano Observatory currently rates Veniaminof as Aviation Color Code Green and Volcano Alert Level Normal.

In modern times the volcano has had numerous small eruptions (over ten of them since 1930); these are located at a cinder cone in the middle of the caldera.

Veniaminof has one of the highest elevations of Alaskan volcanoes. Partly for this reason, it is covered by a glacier that fills most of its large caldera.

Due to the glacier and the caldera walls, there is the possibility for a major flood from a glacier run at some point in the future.

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