Mobile towers could correctly predict rain, study finds

[CAPE TOWN] Distorted cellphone reception that result from rains could be used to monitor rainfall patterns in Africa, a new study shows.

Researchers from Burkina Faso, Côte d'Ivoire and France say there is an increasing need to measure rainfall in Africa because of extreme events such as droughts and floods, but the high cost of such venture using radar data requires an alternative solution.

They, therefore, tested the potential of using microwave links from two mobile telecommunication towers separated by 29 kilometres in Ouagadougou, Burkina-Faso’s capital, to measure rainfall from 26th June to 20th August 2012.

“These results demonstrate the potential interest of exploiting national and regional wireless telecommunication networks for monitoring rainfall in Africa.”

Researchers, Geophysical Research Letters

According to the study published in Geophysical Research Letters last month (18 August), the loss of signal along the base station link, which was attributed to rain, was used to estimate rainfall. The findings were compared with rain gauge data.

Ali Doumounia, the lead author and a doctoral researcher in applied physics at the Université de Ouagadougou, Burkina Faso, says they were able to correctly detect 95 per cent of rainy days during the study period.

“These results demonstrate the potential interest of exploiting national and regional wireless telecommunication networks for monitoring rainfall in Africa,” the researchers note in the journal.

Doumounia says the evidence that extreme environmental changes may be fueling changing climate, especially in urban areas due to population growth and rapid land use, calls for improved understanding of rainfall patterns.

“Precipitation [rainfall] needs to be accurately measured with high spatial and temporal resolution to study and monitor this changing risk, but the operational ground network is sparse … in Africa,” he adds.

François Zougmore, a co-author and director, laboratory of materials and environment at the Université de Ouagadougou, notes that as new questions arise on the variability of rainfall, improved measurements over poorly monitored regions make the new technique a welcome option.

Zougmore explains that all areas in each African country are not totally covered by commercial microwave links and in rural areas the cellular phone network is sparse, adding that the microwave link information can be combined with satellite data to correct the biases in real-time satellite estimates.

Hagit Messer, a professor at the School of Electrical Engineering, Tel Aviv University in Israel, says using the technology to measure rainfall is promising for improving long-term weather prediction.

Messer adds that special purpose methodological equipment is expensive, needs installation, maintenance, energy source and communication network, so it is not widely used in underdeveloped areas.

“The [study’s] preliminary results are good,” Messer tells SciDev.Net. “Indeed, in the experimental setup, they used a limited number of long microwave links in relatively low frequencies, but the results show good agreement with local [rain] gauges.”

Link to abstract in Geophysical Research Letters

This article has been produced by SciDev.Net's Sub-Saharan Africa desk.