  This study focuses on the validation of high-resolution regional reanalyses
to understand their effectiveness in reproducing precipitation patterns over
Italy, a climate change hotspot characterized by coastal sea-land interaction
and complex orography. Nine reanalysis products were evaluated, with the ECMWF
global reanalysis ERA5 serving as a benchmark. These included both European
(COSMO-REA6, CERRA) and Italy-specific (BOLAM, MERIDA, MERIDA-HRES, MOLOCH,
SPHERA, VHR-REA\_IT) datasets, using different models and parametrizations. The
inter-comparison involved determining the effective resolution of daily
precipitation fields using wavelet techniques and assessing intense
precipitation statistics through frequency distributions. In-situ observations
and observational gridded datasets were used to independently validate
reanalysis precipitation fields. The capability of reanalyses to depict daily
precipitation patterns was assessed, highlighting a maximum radius of
precipitation misplacement of about 15 km, with notably lower skills during
summer. An overall overestimation of precipitation was identified in the
reanalysis climatological fields over the Po Valley and the Alps, whereas
multiple products showed an underestimation of precipitations across the
North-West coast, the Apennines, and Southern Italy. Finally, a comparison with
a time-consistent observational dataset (UniMi/ISAC-CNR) revealed a non-stable
deviation from observations in the annual precipitation cumulate of the
reanalysis products analyzed. This should be taken into account when
interpreting precipitation trends over Italy.
