Technique that sprays water in air to bring rain
Clouds form when water droplets gather on dust or other particles in the air. Increasing the amount of salt particles in the atmosphere allows more of these water droplets to form the clouds denser and more reflective.
London: Clouds form when water droplets gather on dust or other particles in the air. Increasing the amount of salt particles in the atmosphere allows more of these water droplets to form the clouds denser and more reflective.
Now, a team from universities of Manchester, Washington and Edinburgh has found a technique called "Rayleigh Jet" which can spray a fine jet of water that breaks down into small droplets in the sky.
The liquid droplets evaporate quickly, leaving behind just the salt particles.
These particles can be generated from specially-built ships that could travel the world's oceans spraying salt particles into the air where they then hang in the atmosphere for several days until they return to the earth as rain, researchers said.
It can be incredibly energy intensive to propel water high into the atmosphere and the energy required had never really been tested before.
"Our paper optimises the salt particle sizes to produce the required change in cloud reflectance for the least energy cost. It is an important finding if these techniques should be needed in the future," said Paul Connolly from University of Manchester.
The 'Rayleigh Jet' method could produce the desired effect using 30 megawatts of energy, about the same energy that two large ships produce, the scientists noted.
The technique is named after Lord Rayleigh who provided the theory.
Marine cloud brightening is a reversible geo-engineering method proposed to mitigate rising global temperatures.
It relies on propelling a fine mist of salt particles high into the atmosphere to increase the albedo of clouds - the amount of sunlight they reflect back into space.
This would then reduce temperatures on the surface, as less sunlight reaches the earth.
The paper was published in the journal Philosophical Transactions of the Royal Society A.