Rare clouds seen above Antarctica

Source: AAP, Tuesday August 1, 02:17 PM

Extreme weather conditions have produced a rare cloud formation over Australia's Mawson station in Antarctica.

Meteorological officer Renae Baker captured spectacular images of the nacreous clouds, otherwise known as polar stratospheric clouds, late last month.

Reflecting like an airborne mother-of-pearl shell, the cloud colours are produced when fading light at sunset passes through water-ice crystals blown along a strong jet of stratospheric air more than 10 kilometres above the ground.

A weather balloon measured temperatures down to minus 87 degrees celsius when the photographs were taken.

"That's about as cold as the lowest temperatures ever recorded on the surface of the Earth," Ms Baker said.

"Amazingly, the winds at this height were blowing at nearly 230 kilometres per hour."

Australian Antarctic Division atmospheric scientist Andrew Klekociuk said the clouds were seldom seen but could have long-ranging effects.

"These clouds are more than just a curiosity," he said.

"They reveal extreme conditions in the atmosphere and promote chemical changes that lead to destruction of vital stratospheric ozone."