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Can cellphones tell you how wet it is outside? (Spoiler alert: Yes)

cell-towersWith the advent of smartphones and the all-important apps that they run, you’d be forgiven for feeling that the sheer possibilities available to us can seem overwhelming at times. Well, here’s something else that cellphones can do that’s a little out of the ordinary: Apparently, they – or, rather, cellular towers – can be used to help measure the rainfall in the immediate area, allowing meteorologists to get a more accurate idea of just how wet their country is. At least, that’s what Dutch researchers have done.

According to a report in New Scientist, a team of scientists from the Netherlands led by Aart Overeem from the Royal Netherlands Meteorological Institute measured rainfall using information provided by T-Mobile. They do this by noting the way raindrops can weaken the radio waves cell towers use to transmit information to each other. Cell towers in the Netherlands are spaced around three kilometers (1.8 miles) apart and transmit a constant signal between each other, meaning that the traditional signal degradation tends to be uniform. Any deviation in signal strength outside of the norm is easily noticeable by someone closely tracking the data.

Overeem’s team studied signals sent between towers in a four month period between June and September 2011, with the signal strength measured every 15 minutes across the approximately 8,000 towers in the Netherlands. To put that figure in some context, the traditional rain gauges in the country measure rainfall every 10 minutes, but there are only 32 of them throughout the entire country. In other words, the information being offered is far more accurate, if slightly slower than the previous method. The result of this analysis were supported by measurements from the traditional gauges for the same time period, and formed the basis of something called a “rainfall map” of the country for the period. This gave a clearer picture of not only how much rainfall there was during those four months across the entire country, but where the rainfall had been centered.

There are real world applications for this type of technology beyond simply checking whether or not one area of Holland is wetter than another; the team from the Royal Netherlands Meteorological Institute say that they are hopeful that some extrapolation of this technique could be useful in improving flood forecasts or providing real-time information about weather conditions in locations where traditional weather-monitoring equipment is unavailable but cell towers are prevalent (third world countries, for example).

That hope is mirrored by Mary Lynn Baeck, a hydrometeorologist at Princeton University, who told New Scientist that she believes Overeem’s approach “has the potential to give good quantitative rainfall estimates for real-time hazards forecasting, as well as regional and global climate model analysis in regions of the world where the impact could be great.”

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