Radar-derived convective storms climatology for Prut River Basin: 2003−2017

Abstract. Weather radar measurements are used to study the climatology of convective storms and their characteristics in the transboundary Prut river basin. The Storm Cell Identification and Tracking (SCIT) algorithm was used to processes the volumetric reflectivity measurements, in order to identify, characterize, and track the convective storm cells. The storm attributes table output of the algorithm was used to separate the convective from the stratiform storm cells, by applying a simple selection criterion based on the average Vertically Integrated Liquid (VIL) values. The radar-derived characteristics of convective storms were used to document the spatial and temporal distributions, and storm properties in terms of duration, traveled distance, movement direction, and intensity. The results show that 94.3 % of all convective storm cells were detected during May–August, with the peak in July. The peak time for convective storm cells occurrence was in the afternoon and evening hours between 10:00 and 18:00 UTC. The average duration of a convective storm was 48.7 min, the average traveled distance was 28 km, and the average movement speed was 8.5 m s−1. The average movement of storms varied with months, but overall most convective storms move from southwest and south-southeast. Also, the analysis shows that the longer-lasting convective storms were the most intense. The spatial distribution of the convective cells reveals yearly variation patterns and hotspots, but also highlights the limitations of radar measurement at longer distances. At the basin scale, the total monthly number of storm cells positively correlates with the precipitation amounts at confidence levels statistically significant.