A weather monitoring system for the study of precipitation fields, weather, and climate in an urban area

The possibility to study the precipitation dynamics with advanced and specific tools is an important task of the research activity addressing the understanding, the modeling, and the managing of rainfall events. Over the last years, the hydrology laboratory of the Department of Civil, Environmental, Aerospace Engineering, and Materials (DICAM) at the University of Palermo, has installed several instruments for the monitoring and the study of precipitation within the urban area of Palermo (Italy). The main instrument of this system is the X-band weather radar, which allows monitoring the precipitation fields with high resolution in space and time. This instrument is supported by a rain gauges network of 18 tipping bucket gauges spread over the observed area, a weight rain gauge, an optical disdrometer, and a weather station. The information provided by different devices can be combined in order to integrate different data and correct errors. In particular, the disdrometer is able to provide the drop size distribution (DSD) that is directly linked to the parameters used to transform radar reflectivity to precipitation estimates. Moreover, disdrometer observations can be used to classify the precipitation events. The rain gauges network data is used to apply a ground correction to the radar precipitation maps. Such an operation is useful to constrain the radar estimate to the observed ground precipitation value. Results obtained from a prototypal version of the system, that considers only the main applications designed, are discussed for a study event. Finally, all of the above instruments are embedded in an integrated early warning system able to provide warnings related to possible flood in the urban area of Palermo.