Developing an impact-based flood forecasting system in Europe relies on understanding the driving forces of hydrometeorological hazards and their consequent impacts. Large-scale climate variability is an important source of spatial and temporal changes in hydrometereological variables, and represents a major component when understanding (sub-) seasonal changes in flood risk.
Are there anomalies in flood occurrence and damage between the different phases of the indices of climate variability?
Are there differences in the frequency and intensity of extreme rainfall between the different phases of the indices of climate variability?
Figure 1. Flowchart representing the methodological framework applied in this study, handled in four steps: (1) collection of two input datasets; (2) extraction of four flood indicators based on input datasets; (3) application of statistical methodology; (4) analysis of results.
We found that positive and negative phases of NAO and EA are associated with more (or less) frequent and intense seasonal extreme rainfall over large areas of Europe. The relationship between ENSO and the Occurrence of Extreme Rainfall and Intensity of Extreme Rainfall in Europe is much smaller than the relationship with NAO or EA, but still significant in some regions. We showed that Flood Damage and Flood Occurrence have strong links with climate variability, especially in southern and eastern Europe.
Furthermore, we suggested that, when investigating flooding across Europe, all three indices of climate variability should be considered, and that the inclusion of seasonal forecasts of indices of climate variability could be effective in forecasting flood damage. However, future research should focus on their joint influence on flood risk.