A Physicist Has an Ingenious Plan to Track Arctic Sea Ice With a Cold War-Era Early Warning Radar

It took U.S. military scientists and defense contractors the entirety of the Cold War to bring the concept to fruition, but it only became operational as the Berlin Wall came crumbling down. Over-the-horizon (OTH) radar surveillance, including the Pentagon’s pre-DARPA “Polar Fox” experiments, bounced high-frequency (HF) radio waves off of Earth’s ionosphere to peer around distant curving horizons as far as 1,800 miles (2,897 kilometers) away.

This high-frequency (HF) “skywave” radar, as the backscatter technique was nicknamed, would have provided…