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Scientists are getting their first glimpse into the inner
secrets of an ice shelf, thanks to the innovative application
of a new radar technique developed by British Antarctic
Survey (BAS). Getting a clearer view of how ice behaves
is important because it will help scientists predict more
accurately how the ice sheet will respond to future climate
change. The results are published this week in the Journal
of Glaciology.
Using phase-sensitive radar – an exceptionally accurate
version of the systems used by ships and aircraft to detect
objects in their path – Dr Adrian Jenkins and colleagues
from BAS studied the internal structure of the enormous
Filchner-Ronne Ice Shelf, as well as the rate at which
the bottom of the ice shelf is melting.
Lead author Dr Jenkins of BAS says, "The radar provides
an unprecedented insight into the flow of the ice shelf.
Internal structures are formed as layers of snow are laid
down each year. These layers produce radar reflections
that give us a totally new view of the internal workings
of an ice sheet. This will help us understand how the
ice flows and improve our ability to predict how the ice
sheet as a whole will evolve in the future, which is important
because growth or shrinkage of the ice sheet has a direct
impact on global sea level."
As well as shedding new light on the makeup of the ice
shelf, Dr Jenkins and his colleagues used the phase-sensitive
radar to measure the rate at which the underside of the
ice shelf is melting. These are the first-ever direct
measurements of ice shelf melting and are extraordinarily
accurate. According to Dr Jenkins,
"The new technique allows us to measure centimetre-scale
changes in the 2-km thickness of the ice. We found that
an average of 1 m of ice is melted from the bottom of
the ice shelf every year. At this rate, all the ice lost
by melting can be replenished by flow of ice from upstream,
so that this part of the ice shelf is showing no signs
of change. Elsewhere in Antarctica ice shelves and ice
streams are thinning and now we have a tool to measure
the thinning rates to unparalleled accuracy."
Contact: Athena Dinar
a.dinar@bas.ac.uk
1-223-221-414
British Antarctic Survey
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