(task) Greenland glacier sheds chunk of ice that covers MANHATTAN | Daily Mail Online

GRS

4 cover

climate change, sea level rise, Arctic

> http://www.dailymail.co.uk/sciencetech/article-3209359/Fastest-moving-glacier-world-sheds-record-breaking-chunk-ice-big-cover-MANHATTAN-300m-frozen-slab.html <http://www.dailymail.co.uk/sciencetech/article-3209359/Fastest-moving-glacier-world-sheds-record-breaking-chunk-ice-big-cover-MANHATTAN-300m-frozen-slab.html>
>
> Fastest moving glacier in the world sheds record breaking chunk of ice big enough to cover MANHATTAN in a 300m thick frozen slab
>
> Sentinel-1A captured the Jakobshavn glacier in western Greenland before and after the event
> Fastest moving glacier in the world shed a chunk of ice measuring around 12.5 sq km
> New face of the glacier has been pushed to furthest easterly location since monitoring began in the mid-1880s
> By Mark Prigg For Dailymail.com </home/search.html?s=&authornamef=Mark+Prigg+For+Dailymail.com> <https://twitter.com/intent/follow?screen_name=@markprigg&tw_p=followbutton>
> Published: 14:55 EST, 24 August 2015 | Updated: 15:20 EST, 24 August 2015
>
> Satellite images show that the fastest moving glacier in the world shed a chunk of ice measuring around 12.5 sq km this week – one of the most significant calving events on record.
>
> Radar images from the European Space Agency's Sentinel-1A captured the Jakobshavn glacier in western Greenland before and after the event, which took place between 14 and 16 August.
>
> Comparing images taken on 27 July, and 13 and 19 August, the new face of the glacier has been pushed inland by several kilometres to what appears to be its furthest easterly location since monitoring began in the mid-1880s.
>
>
> This optical image of Jakobshavn glacier in western Greenland, acquired by Sentinel-2A on 16 August 2015, offers a valuable perspective of the scale of the calving event that took place between 14 and 16 August. The contour indicates the area of ice lost between images acquired on 6 and 16 August.
>
> JAKOBSHAVN GLACIER
>
> The Jakobshavn Glacier drains 6.5% of the Greenland ice sheet and produces around 10% of all Greenland icebergs.
>
> Some 35 billion tonnes of icebergs calve off and pass out of the fjord every year.
>
> Icebergs breaking from the glacier are often so large (up to a kilometer in height) that they are too tall to float down the fjord and lie stuck on the bottom of its shallower areas, sometimes for years, until they are broken up by the force of the glacier and icebergs further up the fjord.
>
> The image time series suggests that between 27 July and 13 August, the glacier advanced westward before the calving caused rapid retreat of the ice front to its position on 19 August.
>
> It is estimated that the glacier lost a total area of 12.5 sq km.
>
> Assuming the ice is about 1400 m deep, this equates a volume of 17.5 cubic km – which could cover the whole of Manhattan Island by a layer of ice about 300 m thick.
>
> The history of this last calving event is also revealed in images taken by Sentinel-2A on 6 and 16 August.
>
> Jakobshavn glacier drains 6.5% of the Greenland ice sheet, producing around 10% its icebergs. This amounts to some 35 billion tonnes of ice that calve every year.
>
> Other similar events have been documented where the glacier parted with 7 sq km of ice, both earlier this year and back in 2010.
>
> Icebergs are often so large that they cannot float away easily. They remain, sometimes for years, stuck on the bottom in shallower areas of the fjord until they finally melt enough to disperse, break into pieces or are pushed out by icebergs coming up from behind.
>
> Studied for over 250 years, the Jakobshavn glacier has helped to develop our understanding of the importance of ice streams and glaciers in climate change, icecap glaciology, and how they affect sea level.
>
> Sentinel-1A and Sentinel-2A are the first two satellites in orbit for Europe’s Copernicus programme. While Sentinel-1A is an all-weather, day-and-night radar imaging mission, Sentinel-2A carries a multispectral imager.
>
> Since radar can ‘see’ through clouds and in the dark, Sentinel-1A it is particularly useful for maritime surveillance, ship safety, sea-ice charting and ice-sheet monitoring.
>
>
> The Sentinels are a fleet of satellites designed specifically to deliver the wealth of data and imagery that are central to the European Commission’s Copernicus programme.
>
> Sentinel-2 carries an innovative wide swath high-resolution multispectral imager with 13 spectral bands for a new perspective of our land and vegetation.
>
>
> Radar images from Sentinel-1A captured the Jakobshavn glacier in western Greenland before and after a massive calving event, which took place between 14 and 16 August 2015. The image composite includes different Sentinel-1A images from 27 July, and 13 and 19 August. The red, green and blue indicate the position of the calving front and other dynamic features on each respective date.
>
> The combination of high resolution, novel spectral capabilities, a swath width of 290 km and frequent revisit times will provide unprecedented views of Earth.
>
> The mission is based on a constellation of two identical satellites in the same orbit, 180° apart for optimal coverage and data delivery.
>
> Together they cover all Earth’s land surfaces, large islands, inland and coastal waters every five days at the equator.
>
> The mission will mainly provide information for agricultural and forestry practices and for helping manage food security. Satellite images will be used to determine various plant indices such as leaf area chlorophyll and water content indexes.
>
> This is particularly important for effective yield prediction and applications related to Earth’s vegetation.
>
> As well as monitoring plant growth, Sentinel-2 can be used to map changes in land cover and to monitor the world’s forests. It will also provide information on pollution in lakes and coastal waters.
>
> Images of floods, volcanic eruptions and landslides contribute to disaster mapping and help humanitarian relief efforts.
>
> Sentinel-2 is the result of close collaboration between ESA, the European Commission, industry, service providers and data users.
>
> The mission has been designed and built by a consortium of around 60 companies led by Airbus Defence and Space, and supported by the CNES French space agency to optimise image quality and by the DLR German Aerospace Centre to improve data recovery using optical communications.
>
> With its multispectral imager and wide swath coverage, the Sentinel-2 mission not only offers continuity, but also expands on the French Spot and US Landsat missions.
>
> Sentinel-2A was launched on 23 June 2015 and Sentinel-2B will follow in the second half of 2016.
>
> Together, these and future Sentinels, in particular the upcoming Sentinel-3 mission, will add further complementary measurements for operational applications and scientific purposes.
>
>
>
>
> Share or comment on this article