## 3 Results
### Overshooting Tops and Hailstorms  
With the criteria described in Section 2.2, the identification of PFs associated with overshooting tops (OPFs) and hailstorms has been carried out for all the PFs with at least 4 precipitating pixels. The two definitions of tropopause (\(Z_{LRT}\) and \(Z_{CP}\)) for the OPFs, and the two criteria, one radar-based and one radiometer-based, for the hailstorms have been used. A preliminary analysis has evidenced how the use of the \(Z_{CP}\) tropopause definition tends to select many PFs with weak scattering signatures (high minimum PCT values at 37 and 89 GHz, not shown). Therefore, only the OPFs detected with the WMO lapse-rate tropopause definition \(Z_{LRT}\) are analyzed in detail in this section. Table 3 reports the number of OPFs detected as a function of maximum heights of different radar echo thresholds. However, our analysis is only focused on OPFs detected with the MAXHT20 proxy, considered as the storm top height [27], since this parameter is strongly related with the most active cloud layers. Tables 4 and 5 report the number of potential hailstorms selected with the radar-based and the radiometer-based criterion, respectively. The number of events found over land and over sea are also reported in each table. Since the minimum brightness temperatures or PCTs at 37 GHz and 89 GHz are good proxies for deep convection and presence of graupel/hail in the cloud, the 50 th and the 10 th percentiles of MIN37 CT and MIN85 PCT for each class are reported. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Over Sea** & **Over Land** & **All Events** \\ \hline N\({}^{\circ}\) of events with & & & \\ T\_MAXHT44 \(\leq-22\)\({}^{\circ}\)C & 224 & 547 & 771 \\
50 th percentile of & & & \\ MIN37 PCT/MIN85 PCT (K) & 234.23/158.66 & 240.39/178.40 & 238.69/173.56 \\
10 th percentile of & & & \\ MIN37 PCT/MIN85 PCT (K) & 180.67/103.22 & 196.91/122.39 & 193.22/116.02 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Total number of potential hailstorms (over land and over sea) detected with the radar-based thresholds. The 50 th and 10 th percentiles of MIN37 PCT and MIN85 PCT distributions for each class are also reported. Figure 8: Distribution of volumetric precipitation (VOLRAIN_KU) intensity classes as a function of the minimum PCT at 89 GHz (MIN85 PCT) and the PF precipitation area. It is worth observing that the number of events found with the DPR-based method is about twice as that found with the GMI-based method, although these look more intense (i.e., associated with lower minimum PCTs). In both cases, the number of events found over sea is almost 50% than those found over land. However, despite their lower number, the potential hailstorms over sea appear more intense (i.e., associated with lower minimum PCTs) than those found over land at the time of the satellite overpass. For both channels the lowest minimum PCT values for the same percentiles are found over sea. The characteristics of potential hailstorms detected with the GMI-based criterion are analyzed more in detail, given the large number of events with weak scattering signatures (higher minimum PCT values) detected with the DPR-based criterion. The diurnal variability of the percentage of OPFs detected with the \(Z_{LRT}\) criterion and the hailstorms detected with GMI-based criterion are reported, respectively, in Figure 9,b. The plots evidence the same behaviors observed for all the deep convection PFs, with similar diurnal variability over land, with a peak observed in the afternoon, and no significant variability over sea. The noisy trend with large oscillations in the curves are due to the low number of available cases, especially for the hailstorms over the sea. A similar behavior is found in the monthly distribution of potential hailstorms detected with the two criteria (DPR-based and GMI-based) reported in Figure 10. The trends are similar, with largest percentage of hailstorms (up to 25%) in the summer over land, and in the fall over sea.