## 4 Discussion and Conclusions

Table 6: Four-year analysis of the seasonal percentage of volumetric precipitation associated with observed OPFs and potential hailstorms detected over land or over sea, normalized to the total volumetric precipitation of all PFs in each season detected over land or over sea. The multiparameter approach allows evaluation of deep convection from different points of view, as well as to underline how, even in the Mediterranean area, extreme scattering signatures, typical of tropical storm structures and observed by TRMM measurements, are found also over the sea. The great variety of atmospheric conditions leads to several combinations of different parameter values that represent various microphysical and dynamical characteristics. Therefore, PFs belonging to a given class based on one proxy are not necessarily the same PFs belonging to same class based on a different proxy. There is also the chance that the number of PFs is not the same in each intensity category because of the specific characteristics associated with each parameter. Therefore, the consistency in the distributions of different proxies used for deep convection detection has been verified, showing that extreme radar echo heights have to necessarily coexist with remarkable low brightness temperature or PCT values. In this context, examples of precipitating systems with maximum 40 dBZ echo heights above 10 km or minimum value of PCT at 89 GHz below 100 K (down to 68 K) are all indicative of strong updraft sustaining high density and larger ice hydrometeors. On the other hand, the multiparameter approach serves as a sanity check to better control spurious effects in the large amount of data available. Cases with extreme maximum radar echo top heights and relatively warm BT values, likely related to mirror echoes (as in [PERSON] et al. [7]), could be misinterpreted if radiometer- and radar-based proxies were not analyzed together. The results obtained for the detection of overshooting top PFs (OPFs) and potential halistorms are consistent with what is observed for the most extreme PFs identified with the multiparameter analysis, confirming the soundness of radar-based or radiometer-based criteria used for deep convection detection. The use of radar-based parameters [23; 27] for OPFs proves it to be an extremely valid alternative to the more common methods based on infrared and visible measurements (e.g., Reference [3; 42]). Although LEO satellites, such as the GPM-CO, have the disadvantage of not providing frequent repeated measurements for a given area, it has the advantage of providing more robust parameters that can describe many aspects associated with severe convection (e.g., OPFs). The DPR-based OPFs identification is subject to the selection of the reflectivity threshold for echo top height, and to the tropopause definition. In this study, the 20 dBZ threshold (MAXHT20) has been selected for OPFs' identification, since it allows identification of more likely the maximum altitude of precipitating particles. Furthermore, the tropopause definition is not univocal because it should not be considered as an impenetrable and well-defined thin level of atmosphere, but rather as a transition layer between two different air masses, in which its definition could be associated with different physical parameters. A sensitivity analysis revealed that the WMO lapse rate tropopause definition seems to be the most appropriate for the Mediterranean area, as opposed to [PERSON] [23] and [PERSON] [27], who found similar diurnal OPF behavior for different tropopause definitions, respectively for the tropics and for the entire globe. The analysis on the OPFs shows similarities with the more general deep convection PFs analysis, in terms of geographical distribution, diurnal, and seasonal variability, since these events are indicators of severe weather conditions and deep convection. Some results of this study, concerning the characterization of OPFs, are in agreement with previous studies [23; 27; 34].