High resolution rainfall estimation from Commercial Microwave Links in the city of Niamey in Niger

Abstract. Commercial microwave links (CML) from cellular phone networks have become a source of opportunistic information on rainfall. In this study we use a dense network of 144 CMLs over the city of Niamey, in Niger, to estimate rainfall with a 15-minute resolution. The validation of these estimates with rain gauges shows that for links located within 2 km of a gauge the correlation of 15-minute time series is around 0.85, and the overall bias is low (0 to 10 % depending which link length and frequencies are considered). The CMLs are well suited to detect and quantify the intense rainfall rates associated with the mesoscale convective systems which bring most of the rain – and often floods – in the region. These good results are obtained with a simple and easily transferable processing chain. The study confirms the interest of CMLs in otherwise data scarce areas.