Australian Weather Calendar: December 2020

December photograph by Ben Broady

Out of this world

Ben Broady is no stranger to shooting the stars, but capturing a rare weather phenomenon known as red sprites was an 'out of this world' feeling for the Kimberley-based landscape photographer. 'I knew that they were this elusive, upper-atmosphere phenomenon, but I'd never been able to catch them before,' Ben says. 'There was a distant storm and I just had a crack, and later when I checked the frame and saw them, I thought "wow!"' Ben says unlike lightning we normally see below the cloud, sprites form in the ionosphere and aren't as visible to the naked eye. He says photographing them remains a bit of a mystery, and the challenge is finding the balance with the camera's exposure settings so as not to brighten up the clouds too much. Ben says while the science behind the weather—including space weather—is mind blowing, for him it's just about the marvel of how beautiful it is. 'Ninety-nine per cent of the time it's just me out there shooting, and I just sit there in awe of mother nature. The Kimberley is such a unique landscape; it's where my heart lies. Nothing else compares to it on this Earth.'

The science

Red sprites are a rare phenomenon which is not very well understood. They can occur out of the top of very powerful thunderstorms, and only last for a fraction of a second. Similar to the process that forms an aurora, sprites are formed by charged particles exiting the top of the storm into the ionosphere. The ionosphere is a layer of the earth's atmosphere, from roughly 50 km above the surface, where solar and cosmic radiation ionise atoms and molecules, thus creating a layer of electrons. This electrically conducting region of the atmosphere is of major importance because it reflects and modifies radio waves used for communication and navigation.