Normally when an area is suffering from drought airplanes are sent up to seed clouds in an effort to encourage rainfall. NewScientist is reporting that in the future we may keep the planes on the ground and in their place shoot a laser into the sky to create rain. Such a laser is the goal of a team based at the University of Geneva.
The team’s current laser works by generating laser pulses which strip electrons from atoms in the air to form what is called hydroxyl radicals. These radicals convert sulphur and nitrogen dioxides into particles which then become seeds to encourage the creation of water droplets. The technique has been shown to increase the total volume of condensed water droplets in a lab setting by 50%. Of course, the lab environment consisted of a chamber with water-saturated air at -24°C.
There has also been evidence of this technique working in the the skies of Berlin, Germany when measured using weather LIDAR, which measures light scattering in the atmosphere. During repeated experiments, the LIDAR has been able to confirm that the density and size of water droplets spike when the laser is turned on.
To be accurate, the laser is currently not capable of producing actual rainfall. The laser’s research team is looking to make that a reality by optimizing the focus, pulse duration, and wavelength of the laser in order to produce droplets which are big enough to become rain.
Read more at New Scientist