ESA : Larsen crack .- Grieta en Larsen C

http://www.esa.int/spaceinimages/Images/2017/01/Larsen_crack

 http://www.esa.int/esl/ESA_in_your_country/Spain/La_grieta_de_Larsen_C                              

Larsen crack

La grieta de Larsen C

1 febrero 2017

Hace ya varios años que apareció una grieta en la barrera de hielo Larsen C de la península Antártica, pero en los últimos tiempos ha ido creciendo más rápido que nunca. 

Gracias a sus radares con ‘visión nocturna’, los satélites Sentinel-1 de Copernicus están vigilando la situación.

Esta animación muestra que la fisura se ha extendido unos 60 km desde enero del año pasado. Y desde principios de enero de este año, se han separado otros 20 km, por lo que, en estos momentos, la plataforma de 350 m de grosor apenas se encuentra unida por un hilo a la península. La grieta ahora tiene unos 175 km de longitud.

Cuando el iceberg se separe definitivamente de la barrera de hielo, será uno de los mayores nunca registrados, aunque es difícil pronosticar cuándo sucederá. Las barreras colindantes, Larsen A y Larsen B experimentaron un proceso similar, con partos espectaculares en 1995 y 2002, respectivamente.

Estas barreras de hielo son importantes, ya que actúan a modo de refuerzo, reteniendo el hielo que fluye hacia el mar.

Los dos satélites Sentinel-1 son fundamentales para descubrir y vigilar acontecimientos como estos, ya que son capaces de proporcionar imágenes de radar de forma continua, a pesar de que la Antártida permanece inmersa en la oscuridad durante varios meses al año.

English Versión:

 

 

 

(5.02 MB)

Details

• Title Larsen crack
• Released 30/01/2017 9:19 am
• Copyright contains modified Copernicus Sentinel data (2016–17), processed by ESA
• Description
  A crack in the Larsen-C ice shelf in on the Antarctic Peninsula first appeared several years ago, but recently it has been lengthening faster than before. Carrying radar that can ‘see’ through the dark, the Copernicus Sentinel-1 satellites are monitoring the situation. The animation shows that the fissure has opened around 60 km since January last year. And, since the beginning of this January it has split a further 20 km so that the 350 m-thick shelf is held only by a thread. The crack now extends around 175 km.
  When the ice shelf calves this iceberg it will be one of the largest ever recorded – but exactly how long this will take is difficult to predict. The neighbouring Larsen-A and Larsen-B ice shelves suffered a similar fate with dramatic calving events in 1995 and 2002, respectively.
  These ice shelves are important because they act as buttresses, holding back the ice that flows towards the sea.
  The Sentinel-1 two-satellite constellation is indispensable for discovering and monitoring events like these because it continues to deliver radar images when Antarctica is shrouded in darkness for several months of the year.
• Id 372459

TAGS

• Click on the tags to find the matching images.
• Activity Observing the Earth
• Mission Sentinel-1

ESA calentamiento global
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@hotmail.com
ayabaca@yahoo.com
Inscríbete en el Foro del blog y participa : A Vuelo De Un Quinde - El Foro!

NASA : Antarctica’s Larsen B Ice Shelf: The Final Act .- Estudio de la NASA de una muestra del hielo Larsen B de la Antártida ha llegando a su Acto Final

NASA research has found that the last section of Antarctica's Larsen B Ice Shelf is likely to disintegrate before the end of the decade.

Un nuevo estudio de la NASA encuentra el último tramo restante de la Antártida de hielo Larsen B, que se derrumbó parcialmente en 2002, se está debilitando y es probable que se desintegran por completo antes del final de la década rápidamente.

More information:

http://www.nasa.gov/press-release/nasa-study-shows-antarctica-s-larsen-b-ice-shelf-nearing-its-final-act

NASA Study Shows Antarctica’s Larsen B Ice Shelf Nearing Its Final Act

A new NASA study finds the last remaining section of Antarctica's Larsen B Ice Shelf, which partially collapsed in 2002, is quickly weakening and likely to disintegrate completely before the end of the decade.

A team led by Ala Khazendar of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, found the remnant of the Larsen B Ice Shelf is flowing faster, becoming increasingly fragmented and developing large cracks. Two of its tributary glaciers also are flowing faster and thinning rapidly.

"These are warning signs that the remnant is disintegrating," Khazendar said. "Although it’s fascinating scientifically to have a front-row seat to watch the ice shelf becoming unstable and breaking up, it’s bad news for our planet. This ice shelf has existed for at least 10,000 years, and soon it will be gone."

Antarctica's Larsen B Ice Shelf is likely to shatter into hundreds of icebergs before the end of the decade, according to a new NASA study.

Credits: NSIDC/Ted Scambos

Ice shelves are the gatekeepers for glaciers flowing from Antarctica toward the ocean. Without them, glacial ice enters the ocean faster and accelerates the pace of global sea level rise. This study, the first to look comprehensively at the health of the Larsen B remnant and the glaciers that flow into it, has been published online in the journal Earth and Planetary Science Letters.

Khazendar's team used data on ice surface elevations and bedrock depths from instrumented aircraft participating in NASA's Operation IceBridge, a multiyear airborne survey campaign that provides unprecedented documentation annually of Antarctica's glaciers, ice shelves and ice sheets. Data on flow speeds came from spaceborne synthetic aperture radars operating since 1997.

 

Khazendar noted his estimate of the remnant's remaining life span was based on the likely scenario that a huge, widening rift that has formed near the ice shelf's grounding line will eventually crack all the way across. The free-floating remnant will shatter into hundreds of icebergs that will drift away, and the glaciers will rev up for their unhindered move to the sea.

Located on the coast of the Antarctic Peninsula, the Larsen B remnant is about 625 square miles (1,600 square kilometers) in area and about 1,640 feet (500 meters) thick at its thickest point. Its three major tributary glaciers are fed by their own tributaries farther inland.

"What is really surprising about Larsen B is how quickly the changes are taking place," Khazendar said. "Change has been relentless."

The remnant's main tributary glaciers are named Leppard, Flask and Starbuck -- the latter two after characters in the novel Moby Dick. The glaciers' thicknesses and flow speeds changed only slightly in the first couple of years following the 2002 collapse, leading researchers to assume they remained stable. The new study revealed, however, that Leppard and Flask glaciers have thinned by 65-72 feet (20-22 meters) and accelerated considerably in the intervening years. The fastest-moving part of Flask Glacier had accelerated 36 percent by 2012 to a flow speed of 2,300 feet (700 meters) a year -- comparable to a car accelerating from 55 to 75 mph.

Flask's acceleration, while the remnant has been weakening, may be just a preview of what will happen when the remnant breaks up completely. After the 2002 Larsen B collapse, the glaciers behind the collapsed part of the shelf accelerated as much as eightfold – comparable to a car accelerating from 55 to 440 mph.

The third and smallest glacier, Starbuck, has changed little. Starbuck's channel is narrow compared with those of the other glaciers, and strongly anchored to the bedrock, which, according to authors of the study, explains its comparative stability.

"This study of the Antarctic Peninsula glaciers provides insights about how ice shelves farther south, which hold much more land ice, will react to a warming climate," said JPL glaciologist Eric Rignot, a coauthor of the paper.

The research team included scientists from JPL, the University of California, Irvine, and the University Centre in Svalbard, Norway. The paper is online at:

http://go.nasa.gov/1bbpfsC

NASA uses the vantage point of space to increase our understanding of our home planet, improve lives and safeguard our future. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records. The agency freely shares this unique knowledge and works with institutions around the world to gain new insights into how our planet is changing.

For more information about NASA’s Earth science activities, visit:

http://www.nasa.gov/earth

NASA

Guillermo Gonzalo Sánchez Achutegui

ayabaca@gmail.com

ayabaca@hotmail.com

ayabaca@yahoo.com

Incríbete en el Foro del blog y participa : A Vuelo De Un Quinde - El Foro!

NASA: Glaciers and Mountains in West Antarctica .- Las montañas y los glaciares de la Antártida Occidental

Hola amigos: A VUELO DE UN QUINDE EL BLOG., la Agencia Espacial NASA, nos informa que :   "Los glaciares y las montañas en el sol de la tarde se ven en una investigación vuelo Operación IceBridge, al regresar de la Antártida Occidental el 29 de octubre de 2014..................
La NASA está llevando a su sexto año consecutivo en octubre de vuelos de investigación Operación IceBridge sobre la Antártida para estudiar los cambios en la capa de hielo del continente, los glaciares y el hielo marino. La campaña de este año vuelve a visitar la sección de aire de la Antártida . Que la capa de hielo recientemente se encontró que era de declive irreversible................

IceBridge utiliza un conjunto de instrumentos incluye altímetro láser que, instrumentos de radar, cámaras, y un gravímetro, que es un instrumento que detecta pequeños cambios en la gravedad. Estos pequeños cambios revelan la cantidad de glaciares han perdido masa Estes. Los investigadores planean medida calculada previamente inexploradas regiones de la Antártida, como las partes superiores de Smith glaciar en la Antártida Occidental, que es el adelgazamiento más rápido que cualquier otro de los glaciares de la región. La misión también tiene previsto recopilar datos en partes de la Península Antártica, como la Larsen C, George VI y Wilkins plataformas de hielo y los glaciares drenan en em Que. El calentamiento de la Península Antártica ha sido el más rápido que el resto del continente.................

Back to Gallery

 

Glaciers and Mountains in West Antarctica

 

Glaciers and mountains in the evening sun are seen on an Operation IceBridge research flight, returning from West Antarctica on Oct. 29, 2014.

NASA is carrying out its sixth consecutive year of Operation IceBridge research flights over Antarctica to study changes in the continent’s ice sheet, glaciers and sea ice. This year’s airborne campaign revisits a section of the Antarctic ice sheet that recently was found to be in irreversible decline.

IceBridge uses a suite of instruments that includes a laser altimeter, radar instruments, cameras, and a gravimeter, which is an instrument that detects small changes in gravity. These small changes reveal how much mass these glaciers have lost. Researchers plan to measure previously unsurveyed regions of Antarctica, such as the upper portions of Smith Glacier in West Antarctica, which is thinning faster than any other glaciers in the region. The mission also plans to collect data in portions of the Antarctic Peninsula, such as the Larsen C, George VI and Wilkins ice shelves and the glaciers that drain into them. The Antarctic Peninsula has been warming faster than the rest of the continent.

In addition to extending the data record of NASA’s Ice, Cloud and Land Elevation Satellite (ICESat), which stopped collecting data in 2009, IceBridge will also help set the stage for ICESat-2 by measuring ice the satellite will fly over.

> Operation IceBridge Antarctic 2014 Campaign

Image Credit: NASA/Michael Studinger

NASA

Guillermo Gonzalo Sánchez Achutegui

ayabaca@gmail.com

ayabaca@hotmail.com

ayabaca@yahoo.com

Inscríbete en el Foro del blog y participa : A Vuelo De Un Quinde - El Foro!