Small coloured flags fluttering atop bamboo poles are a familiar sight in Antarctica, marking safe routes for travel on the sea ice, where cracks and thin ice can pose a danger.
The way they flutter is a good unofficial barometer for how strong the wind is, but the official Ross Island weather designation varies from Condition 3 – normal conditions – up to Condition 1 – when temperatures are so low and wind so strong that people are confined to base.
In the Antarctica Specially Protected Area at Arrival Heights, located between Scott Base and McMurdo Station, physicists from the University of Otago maintain a VLF (Very Low Frequency) radar to eavesdrop on communication signals sent to submarines.
These VLF signals travel for thousands of kilometres and bounce off the ionosphere, and Antarctica is a great place to detect them. The physicists use the signals to study sun flare activity.
Lightning strikes are also detectable in the very low frequency range, and the University of Otago Space Physics Group also maintains a lightning detector at Scott Base that is part of a global lightning detection network.
Voices from Antarctica – listen to the full series
Our Changing World’s Antarctic collection
Listen to a wide range of stories recorded in and about Antarctica from our archives.