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Antarctica's mid-winter darkness broken by 'afterglow' of Tonga volcano

  • Sun Online Desk
  • 15th July, 2022 04:11:56 PM
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Antarctica's mid-winter darkness broken by 'afterglow' of Tonga volcano

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A January volcanic eruption 7000km from Antarctica is lighting up skies in the ice-covered continent.

Niwa says an “afterglow effect” from the Tongan volcano eruption seven months ago is causing the colourful skies.

Antarctica New Zealand science technician Stuart Shaw captured a number of stunning images of the sky in shades of pink, purple and orange.

“Usually in mid-winter, Antarctica is nearly continuously dark, except for a slight ‘nautical twilight’ at around midday which means the horizon is faintly visible in good conditions,” said Shaw, who is stationed at Scott Base.

“This year, we were presented with quite a show, which had most of the station personnel grabbing jackets and running outside with their cameras to look at the awesome colours.”

The colourful skies are caused by remnant aerosols from the eruption in the stratosphere above Antarctica, says Niwa forecaster Nava Fedaeff.

“Stratospheric aerosols can circulate the globe for months after a volcanic eruption, scattering and bending light as the sun dips or rises below the horizon, creating a glow in the sky with hues of pink, blue, purple, and violet,” Fedaeff said.

The aerosols are likely made up of sulphate particles as well as water vapour droplets and sea salt from the eruption under the sea.

“These volcanic twilights are known as "afterglows", with the colour and intensity dependent on the amount of haze and cloudiness along the path of light reaching the stratosphere.”

In New Zealand, dazzling sunsets seen across the country in recent months are also likely due to the Tongan eruption, say scientists.