The COMMON experiment—commercial dual-polarization microwave links for urban rainfall monitoring

Rain-rate estimation using commercial microwave link networks is a valuable alternative to traditional measurements from rain gauges, disdrometers and weather radars. Dual-polarization links, similarly to dual-polarization radar, can significantly improve the rain-rate estimates by providing additional information related to the size and the shape of the raindrops.

The COMMON field campaign, a collaboration between EPFL and EAWAG, is designed to investigate the potential of commercial dual-polarization microwave links for rain-rate retrieval in urban areas. The setup consists of a 38 GHz Ericsson ETSI/MINI-LINK R4 microwave link transmitting at horizontal and vertical polarizations with a 4 s temporal resolution and 0.1 dBm resolution. The transmitter and receiver are separated by a distance of 1.85 km and 50 m in altitude. For validation purposes, 5 optical Parsivel disdrometers with a 30 s sampling temporal resolution and 3 tipping-bucket rain gauges have been installed along the path of the link. Radar reflectivity and rain-rate data provided by MeteoSwiss are also available for the considered region. The data collected during this experiment will allow to investigate important issues related to rain-rate retrieval algorithms (e.g., baseline attenuation, wet antenna effects and the variability of the DSD along the link's path). This contribution focuses on the description of the experimental setup and shows some preliminary results.