Improvements to methods of tracking and recording weather patterns finally make it possible to properly test technologies designed to alter them, say experts.
Weather modification attempts to bring rain to dry areas, or divert storms. But decades of tests have generated only heated arguments and even . All techniques developed so far are essentially unproven.
But new weather tracking technology can change that, said delegates at an this week.
Advertisement
New technologies let researchers follow atmospheric events as they happen, says of the US National Center for Atmospheric Research, Colorado. 鈥淭his really is a new era of weather modification.鈥�
鈥淭here have been big improvements in radar, satellites, and airborne instrumentation, and unmanned aerial vehicle technology,鈥� says Joe Golden of the in Washington, DC, US.
Testing times
It is at last possible to properly test techniques long claimed to wring rain from otherwise barren clouds, he says, like seeding clouds with silver iodide particles to increase formation of droplets.
Bruintjes鈥� team is performing cloud seeding experiments in Australia, using advanced Doppler radar that measures the movement of precipitation as well as its density in a cloud.
鈥淲ith this radar, you can look into clouds, see if your seeding particles create the ice crystals and droplets, and how effectively they rain down,鈥� Bruintjes says.
Elsewhere, groups are starting to use randomised studies to generate the first rigorous statistical tests of cloud seeding. In the trials some randomly chosen clouds are seeded while others are not, and the fate of both groups is tracked.
of the Desert Research Institute in Nevada, US, is leading one such project in Australia鈥檚 Snowy Mountains, where snowpack has shrunk in recent decades.
, although there are still 2 years of the 6-year project left to go.
Sunny for summer
But with more than 150 weather modification projects taking place in more than 40 countries worldwide, not all are waiting for definitive proof that weather modification is possible.
China runs the world鈥檚 biggest weather modification programme, spending more than $100 million per year, Bruintjes says. Suppressing rain during the 2008 summer Olympics in Beijing is just part of that
But it is not clear the programme is working. 鈥淭heir technologies really date to the 1960s and 70s,鈥� says Bruintjes, who visited China last year and spoke with government officials about weather modification projects.
鈥淭here is no evaluation, no scientific literature that can substantiate their claims,鈥� he adds. 鈥淧ersonally I am very skeptical about what they can do.鈥�
Wacky weather
This week鈥檚 conference also attracted some wilder suggestions of ways to alter the weather. For example, one private firm proposes to heat them up to form a plasma and dissipate tornados.
But such plans 鈥渉ave no scientific basis whatsoever,鈥� says Bruintjes. Only two weather modification technologies for cloud seeding have any evidence base, he says 鈥� silver iodide and small pieces of salt called hygroscopic particles.
Joe Golden in February organised a US . 鈥淚t鈥檚 time for a fresh look at hurricane modification,鈥� he says.
