As expected, both the FAR and POD decrease with increasing threshold of the Waldvogel or Mason criterion (Fig. 3). This means that for
higher thresholds an increasing number of damaging hail events are
not detected, whereas less and less non-events are also erroneously
considered as hail days. Consequently, the hail detection criteria can
be fine-tuned over a wide range to meet specific user needs: Either to
maximize the detection probability, resulting in more false alarms, or
vice versa. As a tradeoff, we considered both effects by using the HSS
to determine the thresholds. In all cases, HSS's sensitivity to small
changes in the thresholds is low near the maximum. Exact determination of the appropriate threshold is thus not very crucial.