Everyone has experienced the frustration of poor cell phone reception.
As irritating as this can be, there is actually an unexpected upside: if the interference is due to inclement weather, it suggests that cell signal strength can be an effective means to measure rainfall, and consequently, aid in disaster prevention and relief efforts.
Rain reduces the strength of electromagnetic waves relayed through microwave cell phone towers. Based on this principal, meteorologists can calculate the amount of rainfall in specific, highly localized areas in order to issue alerts for mudslides and flash floods. Not only is this method extremely accurate, but it is also virtually free, which is important for poorer regions of the world. Furthermore, rain can be tracked in real time, thereby giving authorities the ability to issue emergency directives to people impacted by the severe weather.
Using this knowledge could have prevented the loss of over one thousand people on August 14 in Freetown, the capital of Sierra Leone. Following heavy rainfall, mudslides oozed over the city and inflicted immeasurable suffering. There were no calls for an evacuation, because no one knew exactly how much rain fell, and therefore no one anticipated the likelihood of the tragedy.
The benefits of this system are not confined to remote areas, and these methods are being increasingly used in highly developed countries to help city managers reduce sewer overflows. By using the data collected from cell towers, technicians are able to instantly adjust run-off systems and prevent collateral environmental damage.
Interest in this methodology is advancing techniques that can be used to not only report current conditions, but also be used to make more accurate predictions. Newer transmission antennas utilize shorter wavelengths, which can actually gauge the air’s moisture content. In turn, these perceived moisture patterns allow for a considerably more precise forecast of near-term precipitation.
For more information, please read:
Counting raindrops using mobile-phone towers | The Economist