Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Patagonian ice dam studied from space cracks open

19.03.2004


Tourists watch as the 70 meters (220 feets) front wall of the glacier Perito Moreno breaks down Sunday, March 14, 2003 for the first time in 16 years in Lago Argentino, some 3,200 kilometers, (2,000 miles) southwest of Buenos Aires, Argentina.

Credits: AP Photo/Guillermo Gallardo-Telam


A spectacle unseen for 16 years occurred in Patagonia this week: a natural dam of blue ice gave way to crushing lake waters trapped behind it, finally breaking apart.

Watching tourists applauded as a section of the 60-metre high Perito Moreno glacier collapsed and the waters of the dammed southern arm of Lago Argentino surged through it.
Since last October this section – known as Brazo Sur - had been blocked off from the rest of the lake by the glacier’s flowing ice tongue, which extended a solid wall of ice across the narrow water channel.


The 30-km-long Perito Moreno glacier is the most famous part of the Parque Nacional Los Glaciares in Argentina, a UNESCO World Heritage Site.

It is the subject of a long-term study by the University of Innsbruck’s Institute for Meteorology and Geophysics, with in-situ observations supplemented by ESA satellite data.

"We have carried out numerous field studies of Perito Moreno, as well as neighbouring glaciers in the Southern Patagonian icefield," explains project leader Professor Helmut Rott. "We have an automatic climate station installed near the glacier terminus, and stakes placed within the glacier to measure its movement and melting.

"We also make use of radar imagery from ERS-2 and Envisat to monitor areas of accumulation and ablation and keep track of its position.

"What makes Perito Moreno so interesting to us is that it is one of the few Patagonian glaciers that has advanced during recent days. It dams the Brazo Sur on a periodic basis, the previous time being 1988, then some 20 times before that. It first occurred in 1917, and we know it was the first time because a several-hundred-year old forest was submerged as a result."

Once the glacier blocks the channel between the Brazo Sur, water and the main section of Lago Argentino, water and ice commence a kind of duel. Water from melting glaciers and running down from mountain drains into the trapped section of lake: its height rose by eight metres in the last five months; at the time of the fracture the rate of increase was ten centimetres a day.

Inevitably the total force the rising waters exert upon the glacier becomes too much. On 12 March 2004 water began to drain through subsurface fissures, which enlarged into a tunnel. Two days later the ice fractured above the waterline. Sightseers flocked to watch the ice dam give way, a sight which some had feared might never be seen this century due to global warming.

"However our research shows the mass of the Perito Moreno glacier is actually in equilibrium," Rott says. "The snow accumulated up at the top of the glacier in the Andes balances out ice that calves or melts lower down.

"Field studies of mass fluxes, complemented by satellite radar, record 5.5 metres of precipitation falling on the accumulation zone a year, equivalent to about 15 metres of consolidated snow.

"It is also a very deep glacier. Eight kilometres up from the glacier front we measured the ice thickness at 750 metres, whereas at the calving front it is only 160 metres thick.

"This feature of subglacial topography, as well as the comparatively high elevation of the accumulation area, means that is it less vulnerable to changing conditions, such as warmer climate that has led most glaciers in the region to recede significantly during the last 30 years.

"Conversely, the initial damming event in 1917 appears to have been the Perito Moreno glacier’s time-lagged reaction to a pronounced period of cooling in the 19th century, sometimes termed a ’mini Ice Age’."

Following the fracture, the Innsbruck University team will continue to monitor glacial motion and flux across Southern Patagonia - a region containing the largest glaciers in the southern hemisphere outside of Antarctica.

Henri Laur | ESA
Further information:
http://www.esa.int/esaSA/SEM2OFX5WRD_earth_0.html

More articles from Earth Sciences:

nachricht How do megacities impact coastal seas? Searching for evidence in Chinese marginal seas
11.12.2017 | Leibniz-Institut für Ostseeforschung Warnemünde

nachricht What makes corals sick?
11.12.2017 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

Im Focus: Virtual Reality for Bacteria

An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications

Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...

Im Focus: A space-time sensor for light-matter interactions

Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.

The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Midwife and signpost for photons

11.12.2017 | Physics and Astronomy

How do megacities impact coastal seas? Searching for evidence in Chinese marginal seas

11.12.2017 | Earth Sciences

PhoxTroT: Optical Interconnect Technologies Revolutionized Data Centers and HPC Systems

11.12.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>