Hail Climatology for Brisbane, Australia, Derived from Single-Polarization Radar

Severe hail storms are a significant hazard along the central east coast of Australia, with previous events causing billions of dollars’ worth of damage. Knowledge of the spatial distribution of these storms is thus relevant both to forecasters and the insurance industry. Here, the hail hazard in the vicinity of Brisbane is quantified using observations from four S-band single-polarization radars. A three-dimensional radar mosaic with 1-km spatial resolution and 5-min temporal resolution is constructed and used to derive daily gridded fields of several widely used reflectivity-based hail metrics. The ability of these metrics to delineate regions of hail damage is assessed statistically using home insurance claim data as ground truth. The best metric is then used to develop a seven-year climatology of damaging hail for the region. Spatial and temporal variations in hail occurrence are subsequently assessed in the context of the synoptic and mesoscale processes which commonly produce these events.