Radar rainfall estimates and raingauge measurements comparison: the Sesia basin case study during the mesoscale alpine program

For flood forecasting, rainfall data are usually obtained from a sparse network of raingauges, consequently the spatial distribution of rainfall may be poorly described, especially in convective situations. Meteorological radars have several advantages in the context of precipitation estimation because a single radar can provide coverage over a large area with very high temporal and spatial resolution. However, in mountainous basins the use of radar rainfall estimates can be affected by the errors associated with the beam elevation and the variability of precipitation with height. In this paper the raingauge measurements and the radar rainfall estimates are compared over the Sesia river basin that is characterized by the presence of high mountains. The radar data used in this research were collected by the dual-polarized S-band radar SPOL during the Special Observing Period of the Mesoscale Alpine Program. Validation results shown a good level of agreement between raingauge measurements and radar data near raingauge sites and this suggest a combined use of radar and raingauges based on the tuning of radar estimates by raingauge measurements.