Though it might seem odd, researchers from New York University and NOAA have found that as more rain falls, more energy is promulgated throughout the atmosphere. That energy, as they explain in their paper published in Science, quite often winds up being converted to wind.
The researchers came together as part of a study to see what impact more rainfall, due to global warming, might be having on the planet, other than creating floods. They found that as a raindrop falls, friction between the water it contains and the air around it creates heat. That heat then dissipates and makes its way to particles in the air which then convert the heat energy to kinetic energy in the form of wind.
To find all this out, they first calculated how much friction is created when a raindrop falls, and then how much heat is dissipated, in a lab. Next, they turned to the annual rainfall database maintained by NOAA and mapped out different areas where the rainfall appeared to have changed the most over time. They then checked local wind gauge measurements from airports that are also kept in databases around the world. In so doing they were able to first predict how much additional wind an area might have due to excess rainfall, and then compare it against actual rainfall amounts. When the two matched, they knew they had found a way to predict wind patterns in areas depending on rainfall.
But that’s not all. They also found that the increased amount of energy in the atmosphere may actually lead to even more rainfall. This could happen, they say, when rainclouds move into an area where there is more than the normal amounts of energy, thus increasing the strength of thunderstorms which could result in more rain falling during the time they exist.
The researchers were careful to point out that their study does not include the impact of rain falling as part of a large strong system such as a hurricane or tropical storm, as such systems transfer so much energy from the ocean it’s impossible to discern if any additional energy is left over and dispersed into the atmosphere.
Of course, as the researchers note, nothing in science is ever as easy as that, and there are of course many things in the environment that impact wind, such as terrain, density of land, humidity levels, and of course the turning of the Earth. But, they say, their study does show that now falling raindrops must be added to the members list of things that can impact winds in local areas.