1For mobile telephone operators, rain is a nuisance which hampers the effective transmission of communications. In 2007, this interference helped Dutch and Israeli researchers find the solution to a completely different problem. Their idea was to convert the fluctuations of the signal emitted and received by relay antennas into data used to detect rainfall in real time. While the approach is of little interest in Europe, it would be relevant for African countries which, although ill-equipped in terms of weather stations and radars, have a well-established network of relay antennas.

Arrival of the monsoon in Niamey.

••• By using the network of relay antennas, it is possible to monitor the risk of flooding in the tropics •••

2In 2012, French and African teams decided to put the principle to the test in Burkina Faso. Working with Telecel Faso, they demonstrated that the analysis of signals from relay antennas helped detect and quantify the level of rainfall. By linking this data to a hydrological model, they managed to create an application capable of mapping the risk of urban flooding. Rain Cell (Rain Measurement from cellular phone networks) was born.

The monsoon, critical to water resources for Sahelian agriculture.

3Researchers however took it a step further. In 2016, building on IRD’s long-standing presence in Africa, they convinced telephone operator Orange to share their data. This enabled them to test the system in five countries: Burkina Faso, Niger, Mali, Cameroon and Morocco, with the launch of a real-time pilot in Cameroon in 2018. All that remains now is to perfect the business model to ensure Rain Cell’s sustainability and operability.

“Obtaining rainfall data in real time in African cities at high risk of flooding would help our services better anticipate risks; we are interested in the Rain Cell project. This innovative research gives access to weather information by making use of existing infrastructure, i.e. mobile telephone networks.” 
Ernest Ouedraogo, director general of the National Meteorological Agency of Burkina Faso