Rainfall fields monitoring based on satellite microwave down-links and traditional techniques in the City of Genoa

The paper describes different rainfall observing techniques available in the City of Genoa (Italy): the Ligurian regional tipping-bucket rain gauge (TBRG) network and the Monte Settepani long range weather radar (WR) operated by the Ligurian Regional Environmental Protection Agency (ARPAL) and Smart Rainfall System (SRS), a network of microwave sensors for satellite down-links developed by the University of Genoa and Artys srl.

Being SRS and WR the two indirect monitoring systems considered in this analysis, the respective performance of the rainfall measurements was assessed by comparison with the reference observations made in-situ by seven TBRG stations selected within the City of Genoa boundary. The analysis was performed by considering the main precipitation events occurred between January 2017 and December 2018.

The results show an agreement between the precision of the ten-minute rainfall intensity (RI) measurements, quantified by the root mean square errors (RMSE), made by the WR and the SRS system for the seven sites. Similar performance has been also observed when comparing the peak of rainfall intensity and the total rain accumulation with the reference TBRG values for the selected precipitation events.

An assessment of the WR and SRS accuracy in providing the two-dimensional RI fields was also performed by computing the map of the RMSE differences over the City of Genoa territory. It is shown that the SRS RI maps are generally associated with a lower level of RMSE with respect to the WR in the areas that are characterized by a higher density of sensors.