Satellites catch Austfonna shedding ice

25 01 2015
Rapid ice loss in a remote Arctic ice cap has been detected by the Sentinel-1A and CryoSat satellites.

Located on Norway’s Nordaustlandet island in the Svalbard archipelago, parts of the Austfonna ice cap have thinned by more than 50 m since 2012 – about a sixth of the ice’s thickness.

Over the last two decades, from the southeast region of Austfonna has increased significantly, and ice thinning has spread over 50 km inland and is now within 10 km of the summit.

The ice cap’s outlet glacier is also flowing 25 times faster, from 150 m to 3.8 km per year – half a metre per hour.

In the study published in Geophysical Research Letters, a team led by scientists from the Centre for Polar Observation and Modelling (CPOM) at the University of Leeds in the UK combined observations from eight satellite missions, including Sentinel-1A and CryoSat, with results from regional climate models.

“These results provide a clear example of just how quickly can evolve, and highlight the challenges associated with making projections of their future contribution to ,” said the study’s lead author, Dr Mal McMillan.

“New satellites such as Sentinel-1A and CryoSat are essential for enabling us to systematically monitor ice caps and ice sheets, and to better understand these remote polar environments.”

Sentinel-1A, the first satellite developed for Europe’s Copernicus programme, was launched in April last year, while CryoSat has been in orbit since 2010.

Satellites catch Austfonna shedding ice
The main figure (top) shows the rate of ice cap elevation change between 2010 and 2014 observed by CryoSat, overlaid on an image acquired by Sentinel-1A (in 2014). Red indicates that the ice surface is lowering. In the southeast region (green …more

Melting ice caps and glaciers are responsible for about a third of recent global sea-level rise. Although scientists predict that they will continue to lose ice in the future, determining the exact amount is difficult, owing to a lack of observations and the complex nature of their interaction with the surrounding climate.

“Glacier surges, similar to what we have observed, are a well-known phenomenon,” said Professor Andrew Shepherd, Director of CPOM.

“However, what we see here is unusual because it has developed over such a long period of time, and appears to have started when ice began to thin and accelerate at the coast.”

Read more at: http://phys.org/news/2015-01-satellites-austfonna-ice.html#jCp

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