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Huge Cavity Antarctic Glacier Signals Rapid Decay



Huge cavity
– two thirds of the Manhattan area and almost 1000 meters high
Thwaites Glacier at the bottom of West Antarctica is one of several
alarming discoveries reported in the new NASA-led decomposition study
glacier. The results emphasize the need for detailed Antarctic observations
the lower parts of glaciers, calculating how fast the world sea level will rise
climate change.

Researchers
there are some differences between the ice and the foundation stone at the bottom of Thwaites
ocean water can flow and melt the glacier from the bottom. Size and
however, the explosive growth rate of the new hole surprised them. It's great
enough to contain 14 billion tonnes of ice and most of this ice melted
over the last three years.

"We have
suspected of years when Thwaites was not firmly attached to the foundation stone
under it, "said Eric Rignot of the University of California Irvine and
NASA Jet Propulsion Laboratory in Pasadena, California. Rignot is a co-author
a new study published today by Science Advances. "Thank you
on the new generation of satellites, we can finally see the detail, "he
said.

The hollow was
discovered by the help of ice-penetrating radars NASA Action
IceBridge
, 2010 launches air campaign exploring connections
between the polar regions and the global climate. The researchers also used
data from the constellation of Italy
and german
synthetic aperture radar. These very high resolution data can be
is treated with a technique called radar interferometry to discover how the earth is
the surface below is moved between images.

"[The size
of] Coal beneath the glacier plays an important role in melting, ”he said
leading author of the study, Piet. Milillo from JPL. "As more heat and water becomes more
under the glacier, it melts faster. "

Numeric
ice sheet models use a fixed form to depict the cavity under the ice,
instead of allowing the cavity to change and grow. The new discovery means that this limitation is likely to cause these patterns
don't appreciate how fast Thwaites loses ice.

About size
In Florida, Thwaites Glacier is currently responsible for around 4
world sea level rise. It has enough ice to raise the world's ocean
slightly more than 2 feet (65 centimeters) and reverse glaciers
increasing the sea level by another 2.4 meters if everything were ice
lost.

Thwaites is one
the hardest to reach places on earth, but it has become better known
than ever before. US National Science Foundation and British National Fund
The Environmental Research Council is responsible for responding to a five-year rural project
the most important questions about its processes and features. The International
Thwaites Glacier Collaboration
will start field experiments
southern hemisphere in summer 2019-20.

How scientists evaluate ice loss

It is not
to monitor the Antarctic glaciers from the ground in the long term. Instead of
scientists use satellite or air instrument data to comply with it
changes as glacier melts, such as its flow rate and surface height.

Another
The variable function is the glacial earthing line – a place near the edge
a continent where it will rise from the bed and start to swim in the sea water. Many Antarctica
the glaciers are expanding for miles beyond their earthly lines
open ocean.

as
a grounded boat can float again when the weight of the load is removed; a
The glacier that loses the weight of the ice can swim over the ground where it was used. When
this happens, the grounding line resigns inland. It exposes more a
the lower part of the glacier on the sea water, increasing the probability that it will disappear
speed up.

Irregular resignation

Thwaites,
"We discover various retreat mechanisms," Millilo said.
Various processes across 100 miles (160 kilometers)
Glacier lines and ice are placed in front of the glacier
loss from synchronization.

Huge cavity
is located under the glacier main luggage frame on its west side – on the side further
from the Western Antarctic Peninsula. In this region, when tides are rising, and
the earthing line retracts and moves around the zone about 2 to 3 miles (3rd)
up to 5 kilometers). The glacier has got out of the ridge
Base stone with a steady speed of about 0.4 to 0.5 miles (0.6 to 0.8 km) a
since 1992. Despite the steady speed of the grounding, the melt
the rate on this side of the glacier is very high.

"To the East
on the glacier side, the ground line retreat occurs in small channels,
maybe a kilometer wide like fingers that reach under the glacier to melt it
from below, "said Milillo
between 1992 and 2011, doubled from 0.4 kilometers per year
up to 0.8 km (1.2 km) per year from 2011 to 2017. Even with this acceleration
but the melting speed on this side of the glacier is lower than that
West Side.

These results
emphasize that the interaction of the ice ocean is more complex than before
understandable.

Milillo hopes
the new results will be useful for the International Thwaites Glacier
Collaborative researchers preparing for their field work. "Such data is
it is essential that field parties focus on the areas where the activity is, because
the grounding line quickly retreats to complex spatial models, ”he said
said.

"Understanding
information about how the ocean melts, this glacier is very important for the project
its impact on sea level rise over the coming decades, ”said Rignot.

The
Milillo and his co-authors in Science Advances magazine have the name:
Thwaites Glacier, West Antarctica. "Co-authors were at the University University
California, Irvine; German Aviation and Space Center in Munich, Germany; and
Grenoble Alps University, Grenoble, France.

News media contact

Esprit Smith
Jet Propulsion Laboratory, Pasadena, California
818-354-4269
Esprit.smith@jpl.nasa.gov

Brian Bell
University of California, Irvine
949-824-8249
bpbell@uci.edu

Posted by Carol Rasmussen
NASA Earth Science News Team

2019-011


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