London, June 11 (ANI): Meteorologists may be miscalculating how much it rains, for a new study has found that many raindrops travel at “super-terminal” velocities, faster than was thought possible.
Scientists previously thought that all raindrops fall at terminal velocity, a constant maximum speed that is determined by the interplay of gravity and drag.
The velocity for individual drops is considered to be largely controlled by their size: larger drops fall faster than smaller drops, due to their greater mass.
In the new study, Fernando García-García of the National Autonomous University of Mexico and colleagues measured the shadows of natural raindrops passing through a ray of infrared light.
They found that up to half exceed their terminal velocity. Some travel as much as 10 times faster, for their size.
“Others had detected this before, but everybody disregarded it, blaming it on an error,” New Scientist quoted Garcia-Garcia as saying.
The researchers believe that the super-terminal drops may be fragments of larger drops broken apart as they fall.
“If a large drop breaks into several fragments, each drop will have the speed of the large drop, at least temporarily, until the smaller drops slow to their new terminal velocity,” García-García said.
Researchers say that because of this, meteorologists may be overestimating total rainfall by up to 20 per cent.
The study has been published in the journal Geophysical Research Letters. (ANI)