Drivers regulate the speed of their windshield wipers depending on how hard it's raining; researchers believe they could track weather patterns through a GPS that monitors this movement.
"If moving cars could be used to measure rainfall the network density could be improved dramatically," project-leader Uwe Haberlandt, said in a European Geosciences Union news release.
Conventional rain gauges usually give across readings, but there are not enough of them to track precipitation across all of Germany (where the study was conducted).
In one part of the experiment the user was asked to manually adjust the windshield wipers based on visibility. In another part the team used a rain machine to test optical sensors present in most windshield wiping devices. The sensors use infrared lasers that detect when water drops fall on the surface of the device, the sensor can also communicate how much water has accumulated.
"The optical sensors measure the rain on the windshield in a more direct and continuous manner so, currently, they would be the better choice for rain sensors in cars," Haberlandt said.
The researchers also took into account the movement of the car in order to avoid errors. In order to test how the device reacted to speed they mounted the device on a rotating device, which "simulates car speed, under the rain simulator." Knowing how the sensor reacts to speed will allow the team to correct these interferences.
"Our experiments so far were carried out in an ideal and controlled environment. In nature there are external effects like wind, spray from other cars or shielding trees that can affect the readings, and rainfall characteristics are different from the rain simulator," Ehsan Rabiei, Haberlandt's collaborator and the paper's lead author, said.
"The value of using moving cars to measure rainfall is not about a higher accuracy of rainfall measurements but about a much higher number of measurement points," Haberlandt said.
The researchers are already working to get the experiment in motion using a taxi company and a car company.
