Rainfall can be a tricky thing to measure. The amount of rain falling in a given area can change from minute to minute and might be completely different from the amount falling only a few miles away. Many wealthy countries spend large sums of money to build rain gauges over populated areas, and track cloud cover using ground-based radar. But in more rural areas, or in less wealthy countries, those options can be limited or non-existent.Currently, without rain gauges or radar there many communities don’t have any way to accurately measure rainfall. This can be a serious problem in regions where flooding, monsoons, or landslides are common. To solve this problem, some researchers are suggesting a new means of detecting rainfall using devices that are already found in every corner of the world: cell towers.Cell towers made an ideal choice for a few reasons. They’re everywhere, even in relatively impoverished countries that would never be able to afford expensive rainfall-detecting equipment. And they’re pretty much always sending out signals, which means they can be used to provide real-time estimates of the amount of rainfall.
The actual process of using cell towers to measure rainfall is pretty ingenious. Rain degrades cell signals, and clever modeling can work backward from cell strength to determine how much precipitation is in the air. Using real-time data from cell towers, meteorologists can tell roughly how much rainfall a certain area is getting without any special equipment.
This isn’t the most accurate method, but it is the easiest and the cheapest, which makes it perfect for areas without traditional rainfall detection. It also makes a nice complement to those rain gauges and radar screens, because cell towers can provide a second-by-second breakdown of the amount of rain, while radar especially could take hours to update.
This concept is already being used in some regions of Africa, and it’s being trialed in Sweden. But soon, weather forecasts around the world might be using cell tower data in addition to traditional measurements in order to record more accurate rainfalls.

Source: The Economist