Precipitation variability and change in the Calabria region (Italy) from a high resolution daily data-set

The present study aims at improving data availability and quality for the last 80-90 years for dailyprecipitation in the Calabria region (southern Italy). First, the original database was homogenised and the gaps filledin for 129 daily rain gauges for the 1916-2006 period. Then, precipitation variability and change were evaluated at anadequate spatial resolution. Monthly and annual total precipitation (P), number of wet days (WDs), and precipitationintensity (PI) were calculated for each series. With regard to the monthly total precipitation a general negative trend, albeitnot everywhere significant, was detected, in particular for the autumn-winter period, while in summer the tendency wastoward an increase in total precipitation. The monthly behaviour of WDs was not very different from that observed for P:a diffuse negative trend was detected in most months, particularly evident and significant in January, with the exceptionof April and the summer months, for which the tendency was toward an increase. Regarding the PI, a general negativeand often significant trend was found for the entire region and for almost all the months, except summer. Attention wasalso focused on tendencies in the different PI categories, revealing negative trends in high-intensity categories, especiallycoming from the winter season.Finally, running trend analysis revealed that the previously discussed tendencies were not persistent throughout the serieslength, but depended on the period examined. This important aspect should be taken into account when different resultsbased on different time windows are compared.