Tokyo

A three-metre radar antenna was among the equipment carried by Kaoru Sato as she set off for the South Pole late last month. Sato, who is based at the National Institute of Polar Research (NIPR) in Tokyo, will do a pilot assessment for a project that could make the Antarctic home to 1,000 such antennas set up in a circular array some 160 metres across.

The array would fill a major gap in our knowledge of the atmosphere, supporters of the project say. Already, radars around the world provide valuable data on phenomena such as atmospheric energy transfers. Researchers use the arrays to transmit radio waves. They then read their reflections to establish fluctuations in temperature, electron density and wind turbulence.

Such data offer information on how the different levels of Earth's atmosphere interact with each other and with the planet's climate — an important component in the study of global climate change and in understanding global weather circulation. But according to Masaki Ejiri, head of the NIPR project, global models badly need more information about such patterns in the little-studied region of the South Pole's atmosphere. “The unknowns far surpass those anywhere else,” he says of the area.

A better understanding of energy transfer in the atmosphere will also help to answer several other questions, Ejiri says, including whether the current improvement in the ozone layer's condition is likely to be short-lived, and how aurorae affect temperatures in the middle atmosphere.

But Sato's bold mission won't be easy to complete. On current estimates, the circular array would consume more power than Japan's entire South Pole research base, says Toru Sato, Kaoru's husband and an engineer at Kyoto University. Sato believes he can reduce this energy consumption by half.

Other technical problems remain to be solved. One is ensuring that the equipment can withstand the low temperatures in the region. Another is interference with the radar signal by other radio waves. Sato's work with the single antenna will seek to measure this extraneous 'noise' with a view to figuring out how best to neutralize it.

But the project's biggest long-term challenge is to win the tens of billions of yen it would cost to build. Ejiri says that he is “convinced that the project is valuable enough to overcome these difficulties”.