German researchers have come up with a unique and affordable way to measure rainfall across different parts of a region. Researchers said that meteorologists can use 'RainCars,' a GPS-equipped moving car, to measure rainfall and better understand weather patterns across a location.

"If moving cars could be used to measure rainfall the network density could be improved dramatically," said Uwe Haberlandt, one of the researchers from University of Hanover in Germany in a press release.

To test the efficiency of the RainCars, the researchers conducted two experiments. In the first experiment, a participant was asked to adjust the wiper speed manually, depending on the windscreen visibility. The experts found that the front visibility was a good indicator for rainfall intensity. However, manual indicator of visibility is not a reliable factor.

In the second experiment, the researchers installed optical sensors in cars to automate wipers. A rain machine was used to measure liquid via wiper speed. These optical sensors measured the rain in continuous manner, making it a better choice to measure rain intensity.

However, the second experiment can also prove to be an unreliable indicator because the experiments were conducted in controlled environments. Wind and speed can alter rain measurements.

"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," said Haberlandt.

"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.

This finding can be used to manufacture better RainCars. In future, the cars could be employed in field experiments to measure rainfall in and around various locations.

The findings have been published in the journal Hydrology and Earth System Sciences.