Radar opens new window into the ice for Antarctic scientists

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.”