Analysis of possible teleconnections controls on the flood frequency regimes in Italy

This Thesis investigates the influence of large-scale climate teleconnections on flood frequency regimes across Italian river basins. Using the FOCA (Italian Flood and Catchment Atlas) dataset, which provides discharge time series for 631 gauging stations across Italy, the study explores statistical relationships between flood occurrences and six global climate indices: North Atlantic Oscillation (NAO), El Niño–Southern Oscillation (ENSO), East Atlantic–Western Russia (EA–WR), Mediterranean Oscillation Index (MOI), Western Mediterranean Oscillation Index (WeMOI), and Pacific Decadal Oscillation (PDO). Pearson and Spearman correlation coefficients, along with associated p-values, are computed between the annual maximum peak discharge and the global indices using two approaches: year-mean values and 12 overlapping three-month averages. Correlations are evaluated under two data availability thresholds (≥ 20 and ≥ 30 years). The results reveal clear spatial and seasonal heterogeneity in teleconnection influences, with MOI and WeMOI showing particularly strong correlations in autumn and winter, especially in southern and central Italy. While the analysis is statistical and non-predictive, the findings provide evidence that flood frequency in Italy is systematically modulated by large-scale climate variability. This research fills a critical geographic and methodological gap in European literature, offering valuable insights into the development of climate-informed flood risk management strategies.