Sea surface temperature anomalies and severe weather outbreaks in Tuscany (Italy). Evaluation of regional effects of climatic change on hydraulic design

Sea surface temperature anomalies (SSTa) data obtained from Comprehensive Ocean-Atmosphere Data Set (COADS) and NOAA Global Area Coverage (GAC) derived from AVHRR (Advanced Very High Resolution Radiometer) for Central-Western Mediterranean, for the period 1951-1997, are statistically compared with severe weather outbreaks in Tuscany (Italy), in terms of excessive rainfall. Severe weather forecasting at the local scale depends on the ability to assess the detailed thermodynamic character of low level atmospheric flows, and some studies have related SSTa especially to low level moisture, based on the concept of the equilibrium state between sea surface and convective boundary layer. Understanding the quantitative role of SST anomalies in the environment of local severe weather is also needed for the assessment of the effects of global change on extreme rainfalls. Based on recent scenarios, such effects are inferred and the hydrological consequences, in terms of the design of hydraulic works, is studied with some detail for a rural drainage network in Tuscany, Italy.