Analysis of dry spells in Southern Italy (Calabria)

A deficit in precipitation may impact greatly on soil moisture, snowpack, streamflow, groundwater, and reservoir storage. Among the several approaches available toanalyze this phenomenon, one of the most applied is the analysis of dry spells. In thispaper, an investigation of the spatial and temporal patterns of dry spells, in a region ofsouthern Italy, has been carried out on a daily precipitation dataset. First, the frequencydistributions of the sequences of dry days have been analyzed. Then, the regional areasmost affected by dry events have been evaluated at annual and seasonal scale. Finally,the long-term trend of the dry spells has been estimated at annual and seasonal scale.Results show that the lower probabilities of long dry spells occur in the main reliefs of theregion, while the highest values have been detected in the Ionian side. The spatialdistribution of the mean and maximum length values of the dry spells evidenced awest–east gradient. The trend analysis mainly revealed a negative behavior in the durationof the dry spells at annual scale and a positive trend in the winter period.