## 3 Results
### Overshooting Tops and Hailstorms
However, the trends and the intensity of the peaks obtained with the two criteria are not exactly the same. This is due to the lower number of potential hailstorms detected with the radiometer-based criterion, which, at the same time, detects the PFs with stronger convective signatures (e.g., MINPTC37 and MINPT89). In the fall, the warm sea surface temperature and warm sea/cold air interaction lead to strong atmospheric instability. In the spring, the sea water is cooler, and such instability is gen \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 & 118 & 219 & 337 \\
50 th percentile of & & & & \\ MIN37 PCT /MIN85 PCT (K) & 205.69/124.05 & 213.51/137.52 & 212.20/134.39 \\
10 th percentile of & & & & \\ MIN37 PCT /MIN85 PCT (K) & 167.74/91.27 & 178.29/104.23 & 172.84/97.04 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Same as in Table 4, but for the radiometer-based criterion. Figure 9: Diurnal variability of OPFs based on the maximum radar echo top height at 20 dBZ (MAXHT20) and \(Z_{LRT}\) tropopause definition (**a**) and of potential hailstorms based on radiometer-based criterion (**b**) over land and over sea. The percentage is computed as the ratio between the number of OPFs or hailstorms detected in each 1-h bin (over land or over sea) and the total number of OPFs or hailstorms for each surface type. erally weaker until mid-summer, when the sea surface temperature rises again due to solar radiation. The geographical distribution and seasonality of overshooting top events and hail-storms are shown in Figure 11a,b. In addition, in this case, the behavior is similar to what already observed for all deep convection PFs detected using different proxies. Fewer OPFs, mainly located over the southeastern Mediterranean (and almost no hailstorms) are found during the winter. A larger number of both OPFs and hailstorms is observed in spring and fall, almost evenly distributed over land and over sea, while a large number of events is found in the summer mostly over land. These similarities in diurnal and seasonal behaviors can be considered as a sanity check of the procedures and methodologies adopted in the deep convection PF analysis. Figure 11: Seasonal distribution of OPFs obtained with the DPR-based method (Z\({}_{LRT}\) tropopause definition) (**a**) and potential hailstorms obtained with the GMI-based method (based on MIN37 PCT) (**b**), over the study area  
Figure 10: Monthly distribution of hailstorm events identified with the radar-based and radiometer-based criteria over land and sea. For each criterion, the percentage is computed as the ratio between the number of hailstorms detected in each month (over land or over sea) and the total number of hailstorms detected for each surface type. Finally, the percentages of the volumetric precipitation associated with the OPFs and hailstorms in each season (normalized to total volumetric precipitation associated with all PFs for each season), are shown in Figure 12a,b. Both types of events contribute to the total precipitation (considering what satellite observes at the time of overpass) mostly during the fall in conjunction with the southward shift of the storms (also triggered over the sea by the thermal air-sea contrast), with similar contributions over land and over sea. Another peak observed in summer, and it is mostly due to the OPFs or hailstorms occurring over land because of the diurnal convective activity that characterizes this season, especially near the mountainous regions. The lowest contribution of these events to the total precipitation is observed in winter, due to the low frequency of such events and, more generally, of convective atmospheric structures, while the contribution is slightly higher in spring (and more significant over land than over sea).