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Old July 22nd 11, 02:31 AM posted to sci.space.news
Andrew Yee[_1_]
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Default ESA ERS-2 final images focus on changing glaciers (Forwarded)

ESA News
www.esa.int

8 July 2011

Satellite's final images focus on changing glaciers

Some of the last images from ESA's ERS-2 satellite have revealed rapidly
changing glacial features in Greenland. In its final days, the veteran
satellite gave us frequent views of the Kangerdlugssuaq glacier and its
advancing ice stream.

Before it retired on 6 July, ESA's ERS-2 Earth observation satellite entered
an orbit to capture radar images of the same area on the ground every three
days, rather than its previous 35-day cycle.

Images of the Kangerdlugssuaq glacier in eastern Greenland taken from March
to May 2011 show that the ice stream was advancing steadily at about 35 m
per day.

Then, between 19 and 22 May, a 9 sq km piece of the glacier broke up into
icebergs.

Information from this ERS-2 'Ice Phase' is helpful for studying rapid
changes such as landslides, tectonics movements, sea ice and growing crops.

Compared to images of Kangerdlugssuaq taken by sister-satellite ERS-1 in
1992, the latest images show that the ice stream's calving front has
retreated by five kilometres in the past 19 years. The simultaneous thinning
of the ice is also evident in the upper part of the stream.

"The data have revealed continued acceleration and retreat of glaciers in
both Antarctica and Greenland, and are certain to become one of the most
important records of climate change during the satellite era," says
Professor Andrew Shepherd of the University of Leeds in the UK.

The ERS-2 European Remote Sensing Satellite was launched in April 1995 and
has spent more than 16 years in space -- far longer than its design life of
three years.

The main instrument is a synthetic aperture radar (SAR), which images Earth
in practically all weather and lighting conditions.

ERS-2 also provided measurements of ozone, sea-level heights and surface
temperatures.

"Now that ERS-2 is retired, no other flying or planned satellite is able to
accurately detect the grounding line location of ice streams," says Marcus
Engdahl, scientific coordinator of the ERS-2 Ice Phase.

"This will make the data gathered by ERS-2 during its final months all the
more valuable for scientists."

In August 2010, a 245 sq km iceberg detached from the Petermann glacier in
northwest Greenland in a rare event detected by ESA's Envisat satellite.

Through the use of 'InSAR' processing -- a technique that can detect
movements of only centimetres -- the new ERS-2 images reveal that the
calving event at Petermann might not yet be over.

Dr Noel Gourmelen, a research fellow in ESA's Support To Science Element
programme, explains that ERS-2 has revealed "that the tip of the Petermann
glacier is moving widely with the ocean tides, while the remaining glacier
shows more steady movement, revealing that the current tip of the glacier --
an area half the size of the previous calving -- is already partly
detached."

[NOTE: Images and weblinks supporting this release are available at
http://www.esa.int/export/esaCP/SEM2...G_index_1.html ]