An aerial image taken by Nasa scientists flying over Greenland has revealed an abandoned Cold War-era “city” beneath the ice.
The image was captured aboard Nasa’s Gulfstream III jet as a team of engineers probed the Greenland ice sheet below.
A new radar instrument they were testing – the UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar) – was attached to the belly of an aircraft flying over northern Greenland when it detected the abandoned city buried within the barren expanse of an ice sheet.
The abandoned city is a military base called Camp Century, a relic of the Cold War built in 1959 by the US Army Corps of Engineers. It was formed by cutting a web of tunnels under a near-surface layer of the Greenland ice sheet.
It was used as a front for Project Iceworm, which aimed to install a vast network of nuclear missile launch sites that could target the Soviet Union.
“We were looking for the bed of the ice and out pops Camp Century,” said Nasa scientist Alex Gardner, who helped lead the project. “We didn’t know what it was at first.”
After the city was abandoned in 1967, snow and ice continued to accumulate, and the solid structures associated with the facility now lie at least 30 metres (100ft) below the surface.
Until now, airborne surveys that flew over Camp Century have captured only the solid structures, which have appeared as a blip in the layers of ice.
The new UAVSAR radar system looks downward and towards the side, producing maps with more dimensionality.
Nasa scientist Chad Greene, who led the team of engineers and captured the image in April, said: “Our goal was to calibrate, validate, and understand the capabilities and limitations of UAVSAR for mapping the ice sheet’s internal layers and the ice-bed interface.”
He added: “In the new data, individual structures in the secret city are visible in a way that they’ve never been seen before.”
Instruments such as the one used for Dr Greene’s mission are expected to help scientists measure the thickness of ice sheets in similar environments in Antarctica and constrain estimates of future sea level rise.
Gardner said: “Without detailed knowledge of ice thickness, it is impossible to know how the ice sheets will respond to rapidly warming oceans and atmosphere, greatly limiting our ability to project rates of sea level rise.”
