资源环境科技发展态势分析平台

This study investigates changes in precipitation regimes in Tuscany (central Italy) over the 1955-2013 period, by using the precipitation concentration index (PCI) and rainfall amount. The PCI is a dimensionless indicator of the temporal concentration of the precipitation. Different statistical methods were applied over the whole period and two independent sub-periods (1955-1984 and 1985-2013). A p-value <0.05 was chosen as level of significance for all the statistical tests. Main results, coming from 35 weather stations, did not show statistically significant trends of the PCI on annual basis and during winter. In spring and summer statistically significant increases were found, respectively, in two stations in northern Apennine (+1.6/50years) and in four stations in central southern inner areas (+2.3/50years). In autumn one station in northern Apennine showed a significant decrease (-1.9/50years). Sub-periods analysis mainly showed higher values of PCI in the recent sub-period on annual scale (statistically significant along the coast), in spring (significant in northwest and northern Apennine), in summer (significant in central southern inner areas) and during winter (not significant). Considering the year-to-year variability of the annual PCI, statistically significant increasing trends were found in the northern part of Tuscany, while decreasing tendencies were observed in the southern one. Concerning annual rainfall, six stations showed statistically significant decreases (-19%/50years). On monthly basis, two stations exhibited significant decreasing trends in March and two in December (respectively -48% and -37%/50years). Two significant decreases were observed in both June and July (respectively -53% and -63%/50years). One station in northern coast showed instead a significant increase in September (+72%/50years). This investigation represents a further tile in the larger mosaic of analysis of climate change and its different impact on precipitation regime at regional level and supports studies concerning water management in the areas characterized by strong seasonality.