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

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>