Cellular towers in the service of meteorology
Israeli scientists perfected a method using phone service towers to measure rain, snow and even detect fog
Serendipity or a happy accidental discovery, has been a well documented part of the development of science and technology throughout recorded history. From Penicillin to Viagra, x-rays to the cosmic background radiation (the ancient hum left by the Big Bang), chance was there to help those who had an open mind.
Professor Hagit Messer from Tel Aviv University had a small help from lady luck when she realized about 10 years ago that it is possible to dramatically improve the accuracy of environmental monitoring using an unexpected tool - cellular towers - such as the ones found in and around any modern city.
Most modern cell towers have two different sets of antennas. The first are the long rectangle ones which communicate with our Smartphones, the second type are round antennas which are used to communicate using higher frequencies with adjacent to construct the backhaul transmission of the network . Those high frequency stationery antennas are what made Professor Messer's idea possible.
Each time a high frequency electromagnetic wave from a cell tower's antennas moves between towers, it encounters water molecules in the air. While mobile phones broadcast at around 2GHz and are typically not affected by rain and other similar atmospheric conditions, high frequency electromagnetic waves used to communicate data between towers (ranging from 10-40GHz frequencies), do suffer from some measurable loss as they travel between towers.
Most engineers looked at this loss as a problem that needed solving as it interfered with the broadcast, but Professor Messer saw this loss as an opportunity. In 2004 she was appointed as the head of the Porter School of Environmental Studies at the University of Tel Aviv. New to the subject and coming from the field of information technology, Messer decided to conduct a series of talks with the researchers in this area to learn more about what they were working on. When one of them, Professor Pinhas Alpert, mentioned that existing meteorological measurements lacked high resolution data across large areas, she asked how can it be that they have not used existing wireless communication infrastructure. They realized that none of them thought about this idea before.
Of course other researchers around the world have looked into using microwave point-to-point transmission as a way of collecting meteorological information, and one group in Holland also looked at existing measurements in cellular networks, but they quickly gave up on the idea of using them, stating the data was too "contaminated". Messer, with her unique set of skills and knowledge in signal processing, was not deterred. She knew from experience that with the right set of algorithms and relaying on the huge amounts of raw data coming from cell towers day in and day out, she will be able to clean up the signal to a level where she could get some useful information - and she did.
In 2006 Messer and her research group published their initial findings in Science magazine. To her astonishment for a whole week she received one phone call after another asking her for an interview regarding the groundbreaking research. However at the time it was a preliminary study, not much more than an idea or proof of concept.
Skipping ahead eight years into the present, the research team, led by Messer and he colleague Prof. Alpert, has taken the research to a whole new level. The them members have analyzed endless amounts of raw cellular data from all three main cellular companies in Israel, which provided the date it free of charge. They developed more accurate ways to measure meteorological information and added more parameters that they can now measure using their growing database.
While initially they were only able to create maps of rainfall (although with better coverage, tempo-spatial resolution and accuracy than other techniques, including Radar), they can now effectively and accurately measure rain, sleet and snow as well as for the first time detect fog.
Although Messer did apply and receive two patents for the technology, she explained to i24news that she sees her innovation as something which belongs to the public good, and commercializing it is not her top priority, so she encourages other researchers and organizations to use the technology. This does not mean that she is stopping her research on the technology - quite the contrary. Her team is already collaborating on testing and perfecting the technology outside Israel in Africa and in Europe and she is constantly looking for new ways it can be used for both academic and practical purposes.
The technology does have its limitations - for example not every place has cell coverage (especially more remote locations) and you can't measure temperature by monitoring information from cell towers, however when combined with existing meteorological monitoring technologies such as radars and local ground based weather stations, the results show unprecedented level of accuracy that can give better and further weather forecast as well as special warnings about upcoming floods, fog and hail which can all effect both people and crop production.
Iddo Genuth is a technology reporter and editor, covering diverse topics ranging from medicine to mobile apps.