(2) Spatial Variation

Figure A7 compares the spatial distribution of the three annual categorical evaluation metrics among the SPPs. At the hourly scale, the spatial distribution of the categorical metrics exhibits a similar pattern across the five SPPs. All five SPPs are poorer at detecting the actual precipitation occurrences at high altitude. However, they also tend to yield more false alarms at low altitude. The conflicting impacts of elevation on the PODs and FARs of the SPPs have led to lower CSI values, i.e., worse overall hourly precipitation detection performance, at the lower altitude, especially at stations 1–3.
