Development and behaviour of a radar-based operational tool for hailstorms identification

Hailstorms are a common meteorological phenomenon in Spain which causes substantial economic damage especially in spring and summer. During 2000 and 2001, a radar-based application for convective monitoring was developed at STAP (Forecasting and Analysis Techniques Department); in order to improve this nowcasting tool, it is needed to include an advanced procedure to estimate the presence of hail as a complementary module in the operational application. A preliminary study, carried out during 2001, showed that the Waldvogel technique, VIL (vertical integrated liquid) density and the hail detection algorithm (HDA) are the methodologies which proved more accurate in our latitudes.Throughout the spring and summer of 2001, all available information about hail events (time, place and hail size) and about storms without hail was used for tuning an experimental module to detect severe and non-severe hailstorms, taking into account the selected algorithms. During 2002, further information about storms was gathered in order to assess the behaviour of the developed hail module. Afterwards, a new module calibration was carried out with the information of the complete storms data set of 2001 and 2002. With this new calibration, the hail module became an operational tool during the spring and summer of 2003. Currently, the verification of the operational module using the data from the storms in 2003 is being elaborated. The aim of this work is to put forward the calibration procedure carried out, the verification results of 2002, and the performance of the hail estimate module in selected cases during 2003 in Spain.