Otago University's Dr James Brundell and Myles Thayer recently replaced an old antenna at Scott Base in Antarctica. Photo / Supplied
Otago University's Dr James Brundell and Myles Thayer recently replaced an old antenna at Scott Base in Antarctica. Photo / Supplied
Herald science reporter Jamie Morton is profiling a series of new studies taking place in Antarctica, before his return to the frozen continent next month. Today, he talks to Otago University's Dr James Brundell.
Piggy-backing on the world's military radio signals has been helping New Zealand scientists understand how space weather affects the technology we use every day.
And of all places, they've been doing it from Antarctica.
Geomagnetic storms are a temporary disturbance of the magnetosphere, which surrounds our planet and is formed by the interaction of the solar wind and Earth's magnetic field.
When giant explosions on the sun - or solar flares - send energy, light and high-speed particles into space, the solar wind shock waves typically strike Earth's magnetic field 24 to 36 hours later.
Coronal mass ejections - eruptions of gas and magnetised material from the sun - similarly have the potential to wreak havoc on satellites and Earth-bound technologies, disrupting radio transmissions and causing transformer blowouts and blackouts.
Such space storms have also been implicated in corroding New Zealand's pipelines - and might have even played a role in Auckland's recent fuel crisis last year.
"We use Antarctica as a vantage point to access information in the near-Earth atmosphere because here, the magnetic field of the Earth is more directly linked to space," explained Otago University physicist Dr James Brundell, who recently returned from an expedition to the frozen continent.
A radio receiver placed near New Zealand's Scott Base constantly listened to very low frequency (VLF) bands of radio, which then sent information back to the university.
While commercial AM radio stations broadcast at around 1000 kHz, VLF worked in the 3-30 kHz range and could capture solar activity - and even lightning strikes.
When giant explosions on the sun - or solar flares - send energy, light and high-speed particles into space, the solar wind shock waves later strike Earth's magnetic field. Photo / 123RF
One source of radio waves Brundell and his colleagues used was the radio transmitters used by the world's military.
Although they couldn't interpret their messages, they could use the radio source to monitor the upper atmosphere.
"We piggyback on military radio signals to monitor how space weather, generated by the sun, impacts our atmosphere and the technologies we use every day," he said.
"Satellites, GPS and power networks and mobile phones can all be affected.
Auroras, like this one seen from Antarctica, are the result of particles in solar winds colliding with atmospheric gases. Photo / Becky Goodsell, Antarctica New Zealand Pictorial Collection, 2015
"Our monitoring gives us a better understanding of the volatility of near-Earth space and how we could lessen the impact of space weather events."
They also used the radio receiver at Scott Base to capture the "crackle" of lightning, which generated signals at VLF that travelled right around the planet.
While lightning strikes were rare in Antarctica, around the world there are many lightning strikes each second that could be heard in the continent.
"Being part of the lightning network allows us all to form a bigger picture of how lightning behaves," Brundell said.
"Our monitoring gives us a better understanding of the volatility of near-Earth Space and how we could lessen the impact of space weather events," Dr James Brundell said. Photo / Supplied
"Our data has helped to discover that lightning in ash clouds can signal a volcanic eruption. This has positive implications for communities and airlines as an early warning system."
On the ice, Brundell and his team were able to replace an old antenna that was disrupted by wind noise.
Antarctica New Zealand's acting chief scientific advisor, Dr Fiona Shanhun, said the university's work in Antarctica filled a gap in two important research groups: the World Wide Lightning Location Network (WWLLN) and Antarctic-Arctic Radiation-belt (Dynamic) Deposition – VLF Atmospheric Research Konsortium (AARDDVARK).
"Without their work in the Ross Sea region, it would be more challenging to triangulate lightning signals or to monitor solar activity."
