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Robot ‘dolphins’ reveal why Antarctic ice caps are melting: Deep-sea gliders show swirls of warm water reaching the surface
- The ‘gliders’ measure 6ft 6in (2 metres) and cost $240,000 (£151,300) each
- Built-in sensors track temperature and salinity in depths of the Weddell Sea
- Measurements reveal how vast eddies drive heat into shallower waters
- These swirls of water are being blamed for causing coastal ice to thaw
- Gliders can be left for months, and were remotely controlled from Norwich
For the first time, swirls of warm water have been spotted reaching shallow regions of the seas around the Antarctic.
By diving beneath the ice caps, a series of 6ft 6in-long (2 metre) yellow ‘gliders’ with built-in sensors have been able to track the temperature and salinity of the depths of the Weddell Sea.
These measurements have revealed how vast eddies – or swirls of water – drive the heat into shallower waters, causing coastal ice to thaw.
The yellow ‘gliders’ (pictured) measure 6ft 6in (2 metres) long, cost $240,000 (£151,300) each and feature built-in sensors that track temperature and salinity in the sea off the coast of Antarctica. These measurements have revealed how vast eddies – large swirls of water – are driving heat into shallower waters in the region
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These eddies transport the warm salty water towards the Antarctic continental shelf.
It is hoped that the findings, published today in the journal Nature Geoscience, will help refine ocean and climate models, so scientists can more accurately predict the rate at which ice sheets will retreat and how quickly global sea level will rise as a result.
This warmer water is normally found hundreds of metres deep within the Southern Ocean, but how it reaches the shallow water around Antarctica had not been seen until now.
The gliders were remotely controlled from Norwich, more than 10,000 miles (16,100km) away, and they sent data back via satellite mobile phone technology every few hours for two months.
The findings confirm theories about how heat moves south, and set benchmarks to track climate change.
Each of the battery-powered gliders cost $240,000 (£151,300), and can be left for months at a time, diving and surfacing with tiny adjustments to buoyancy. They were remotely controlled from Norwich, more than 10,000 miles (16,100km) away, and sent data back via satellite mobile phone technology every few hours
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The UN panel of climate scientists claim both Greenland and Antarctica are losing mass and raising sea levels.
The international study was led by the California Institute of Technology.
Each of the battery-powered gliders cost $240,000 (£151,300), and can be left for months at a time, diving and surfacing with tiny adjustments to buoyancy.
Co-author Professor Karen Heywood, from University of East Anglia’s Centre for Ocean and Atmospheric Sciences, said: ‘Our robots help us to build up a picture of underwater conditions by collecting data on water salinity, temperature, and oxygen levels.
‘The results have identified ocean features that could not feasibly have been studied by any other means.
‘A revolution is underway in Antarctic data.’
These eddies transport the warm salty water towards the Antarctic continental shelf in the Weddell Sea (marked). This warmer water is normally found hundreds of metres down throughout the Southern Ocean, but how it reaches the shallow water around Antarctica had not been observed until now
It is hoped that the findings, published today in Nature Geoscience, will help refine ocean and climate models, so scientists can more accurately predict the rate at which ice sheets will retreat and how quickly global sea level will rise as a result. A ship on the ice in the Weddell Sea is pictured
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‘This research was particularly challenging because the seawater quickly freezes to form sea ice and can trap the sea gliders, just like Shackleton’s ship Endurance was trapped in the same area 100 years ago,’ she added.
One of the three gliders got lost during the study, but Professor Heywood said it still worked out cheaper than a similar trip in 2007 which required a ship costing $30,000 (£18,900) a day, with many stops, to collect less data.
Elsewhere, 3,600 free drifting ‘Argo floats’ have been deployed worldwide since 2000 to help monitor temperatures and salinity in the seas.
SATELLITE’S PLOT THE MELTING ICE OF ANTARCTICA
While rising sea levels and changing global temperatures are already known to be a consequence of climate change, the GOCE satellite has found that gravity is weakening where ice is melting the fastest. The results show that the thinning ice sheet from November 2009 to June 2012 caused local variations (pictured)
An Esa satellite recently spotted an unusual consequence of the melting of ice in Antarctica.
While rising sea levels and changing global temperatures are already known to be a consequence of alleged manmade climate change, the GOCE satellite – which was not intended to study the effects of a warming climate – has found that gravity is weakening where ice is melting the fastest.
The results show that the thinning ice sheet from November 2009 to June 2012 caused local variations in gravity, measured by the satellite.
The GOCE satellite burned up in Earth’s atmosphere as planned in November 2013 after four years in orbit.
During its mission it measured Earth’s gravity in unprecedented detail, detailing where it was weakest and strongest on the surface.
In the air, drones have also been used by organisations such as Nasa to monitor ice.
Katharina Nygaard, of manufacturer Kongsberg’s subsea division, estimated the firm had a quarter of a world market of 800 gliders.
Demand ‘is growing in the marine research world along with small but noticeable uptake by defence and commercial operators,’ she said.
In the Arctic, gliders are tracking higher temperatures that are driving fish stocks north.
‘We’ve moved from prototypes to the more regular use of gliders in the last year,’ said Peter Haugan, professor at the University of Bergen in Norway.
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