Hail detection using single-polarization radar

Within the framework of the project ``Development of a product for detection of severe weather phenomena using non-Doppler radar data'' (KNMI project 2301), a tool for the detection and display of severe weather phenomena related to convective systems, like wind gusts and summer hail, is being developed. Currently, KNMI operates two Gematronik C-band Doppler radars which are performing low-elevation volume scans every 5 minutes and extensive volume scans every 15 minutes. From the low-elevation volume scans, a ``pseudo constant-altitude plan-position indicator'' (pseudoCAPPI) of the radar reflectivity and an echotop product, which presents the maximum height of the echo for each pixel, are extracted. Ground clutter is removed from the pseudoCAPPI image using a statistical method. This report describes the development of the first new sub-product: a tool for the detection and display of summer hail. This hail detection product is to be used for nowcasting of the development and movement of summertime thunderstorms. In addition, an archive of this hail detection product could be a useful reference for e.g. insurance companies.