Antarctic mission for purifying molecule

[dricia]

A world-first mission to shed light on a mystery molecule that cleans the air of greenhouse gases will soon depart for Antarctica.

The Australian Antarctic Division's summer season begins when icebreaker Aurora Australis leaves Hobart on Thursday.

One of the major international projects will examine a little-understood naturally occurring molecule called hydroxyl that destroys gases like methane and industrial chemicals.

Understanding how much greenhouse gas has been removed from the atmosphere by hydroxyl over time could hold the key to more accurate climate change modelling.

Ice cores up to 250 metres long will be extracted to measure pre-industrial levels of hydroxyl and compare it to current levels.

"This is really pushing the limits of our understanding," CSIRO atmospheric scientist Dr David Etheridge said on Tuesday.

"This process has been measured in the atmosphere for the last 10 to 20 years but going back into the past it is completely unknown."

Scientists will work from a temporary lab at Law Dome, a remote section of the frozen continent some 100km from Australia's Casey Research Station, for three months.

They'll melt hundreds of kilograms of ice to produce 30 litres of air samples.

"The concentrations we're looking for are so minuscule it's like trying to find a few particular grains of sand amongst the trillions on a beach," Dr Etheridge said.

Air samples will be sent to labs in Australia and the US for analysis, which could take up to a year.

Heavy snowfall at Law Dome has trapped air for hundreds of years.

"That site is the only place on the planet where we can expect to get this measurement and get it accurately," Dr Etheridge said.

More than 500 expeditioners will travel south on the Aurora Australis or by plane over the summer for research projects.