ANALYSIS OF RADAR AND RAIN-GAGE MEASUREMENTS FOR A CRITICAL METEOROLOGICAL EVENT IN TUSCANY

In this paper, some considerations are given to the employment of C-ba nd polarimetric weather radars for rainfall estimates. The most common error sources are discussed, such as ground clutter and propagation a ttenuation effects, together with decorrelation in the sampling at the ground between radar and raingauge measurements, which can be quite s ignificant in radar systems located in hilly regions, as is the case o f the Arno basin in Tuscany. Since the main objective from a hydrologi cal point of view is the estimate of rainfall at ground, integrations and comparisons are needed between radar and raingauge data, which are characterized by different time and space sampling. The paper is then focussed mainly on this problem and a technique is presented in order to improve radar based rainfall estimates through the integration wit h raingauge data, in order to enhance the correlation between the two types of measurements. Such a method is finally applied to a serious m eteorological event which affected the Arno basin on October 1992.