Thousands of aircraft that fly over the Earth every day contribute significantly to CO2 emissions that pollute the air. But their influence on the climate is not limited to this. A new study has shown that airplanes repeatedly - sometimes 10 times - increase the intensity of precipitation in the region.
It all started when Dmitry Moiseev, a researcher at the University of Helsinki, drew attention to the oddities in the radar data: very narrow, ribbon-like cloud clusters became sources of more abundant rain and snowfall than large cloud arrays. Their location provided a clue to the problem - the proximity to the Helsinki Vantaa airport.
To find out the dependence of the level of precipitation on the airplanes in the air, the researchers studied the data stored at the university for 10 years. They checked the data against the historical flight trajectory records and found that in most cases the aircraft passed within 2-10 km of the recorded strip clouds.
How can this be explained? Contrary to popular belief, water can be in liquid form and at temperatures below 0 ° C - under certain circumstances. Water droplets turn to ice faster if there are points for its crystallization - for example, dust particles. And in clouds, where the amount of impurities is small, water droplets can remain liquid down to -40 ° C.
This state can be maintained until the passing plane "shakes" them. As the liner passes through the cloud of supercooled droplets, the change in air pressure freezes them. An intense chain reaction begins, and water falls out in the form of precipitation, repeating the route of the flying plane.