An Atmospheric Trick May Have Helped A Ukrainian Missile Battery Find And Sink The Russian Cruiser ‘Moskva’

'Moskva' sinking.

In days and weeks after a Ukrainian navy anti-ship missile battery sank the Russian Black Sea Fleet cruiser Moskva on April 13, a lot of rumors circulated.

Many of the rumors attempted to explain how a navy with virtually no big ships or aircraft could defeat a navy with lots of big—and heavily-armed—vessels and planes. Some of the rumors hinged on the assumption that the Ukrainians required foreign help in order to strike Moskva.

Did one of the Ukrainian navy's Turkish-made Bayraktar TB-2 drones sneak up on Moskva and pinpoint her location, 80 miles south of Odesa, for the Neptune battery? Did a high-flying U.S. Navy Boeing P-8 patrol plane relay the critical coordinates?

Neither, apparently. According to an eyebrow-raising new story in Ukrainska Pravda, the Neptune battery—a quad launcher and its associated radar—found and hit Moskva mostly on its own.

The assistance the battery did receive ... came from nature. An atmospheric phenomenon called "temperature inversion" created a kind of channel for radar waves that allowed them to travel over the curve of the horizon and back.

"Nature itself unexpectedly helped Ukraine on April 13," Ukrainska Pravda reporter Roman Romaniuk wrote. "The operators of the Neptune should not have reached Moskva with ordinary radar, but this is exactly what happened."

On the afternoon of April 13, the Neptune battery's radar operator registered, on his screen, a large blip south of Odesa. "There could be only one object of a similar size in this sector of the Black Sea—the flagship of the Black Sea Fleet of the Russian Federation, the cruiser Moskva," Romaniuk wrote.

A Neptune battery.

"But how could an ordinary radar show an over-the-horizon target at such a distance?" Romaniuk asked. "As Ukrainian rocket engineers are convinced beyond doubt, nature itself sided with the defenders."

An atmospheric inversion is a boundary layer in the air where the usual temperative dynamic—warmer air below, cooler air above—switches. Above the inversion, the air is warmer than it is below the inversion.

The inversion, which might occur hundreds or thousands of feet above the surface, is only so thick. A few hundred or thousand feet higher, the atmosphere reverts back to its usual temperature dynamic: higher is colder.

Think of the inversion as an invisible ceiling. Stuff tends to accumulate at the altitude where the temperature abruptly changes. Clouds and pollution, for instance. Electromagnetic waves, too.

When the weather is just so and an inversion forms at the right place and altitude, a radar that normally sees only as far as the horizon—30, 40 or 50 miles, depending on the radar's height—might suddenly see over the horizon. That's because the radar waves are channeled over the curve of the Earth by the inversion. Scientists call it ‘ducting.’

It's hard to anticipate these conditions. So the Ukrainian radar operator was understandably confused when Moskva first appeared on his scope that April afternoon.

But not for long, Romaniuk explained. "After a few minutes of heavy hesitation and consultation, he gave the command ‘launch’—and two missiles flew towards the Russian cruiser."