Alps mission out to solve gravity puzzle

This $100m plane will track gravity waves created when winds strike mountain ranges. Photo / NSF

A sleek Gulfstream V worth nearly $100 million is set to soar into the South Island next month, but it won't be carrying magnates or celebrities.

Instead, the highly-modified corporate jet will have onboard some of the most sophisticated scientific technology ever sent into the air.

The United States-based High-performance Instrumented Airborne Platform for Environmental Research (Hiaper) aircraft will play a starring role in a huge, multi-national scientific study centred on the South Island over the next two months.

Combining more than 100 researchers from the US, UK, Germany, Australia and New Zealand, the Deepwave project sets out to unravel the mysteries of gravity waves, a vital but little-understood atmospheric element.

Gravity waves form when winds strike a large obstacle, such as a mountain range, sending ripples hundreds of kilometres across land and water, and vertically into the outer reaches of our atmosphere.

"We know they're there, but nobody really realised until only recently just how much of an effect on the weather they had," said Tony Bromley, a meteorologist with the National Institute of Water and Atmospheric Research.

While it had been established gravity waves affected the weather on a global scale, there was still debate over the scale of their influence.

"Most people would agree that their influence is quite large, but how large, and how it all exactly happens, nobody really knows."

The project was initially to be held around the Andes mountains in South America, before scientists instead set their sights on the Southern Alps.

The alps are considered a "hot spot" for gravity waves, as the seasonal positioning of the southern circumpolar jet system over their mountainous topography makes for strong gravity waves.

"Because there are no other influences from terrain, you get this nice, smooth flow on the western side right across the Southern Ocean, and then bang, they hit the Southern Alps and you get the uplifting effect," Mr Bromley said.

Within these waves, the Gulfstream V will fly up to 20 missions at heights of up to 12,800m, extending to Tasmania and deep into the subantarctic Southern Ocean.

Gulfstream V

• Worth nearly $100 million.

• Two-month scientific study in South Island.

• Involves 100 researchers from the US, UK, Germany, Australia and NZ.

• Unravels the mysteries of gravity waves.

• To complete up to 20 missions.

• Fly to heights of up to 12,800m.