FIGURES CAPTIONS
Figure 1: Mean annual percentage of zero-flow days at the annual, summer and winter timescales
Figure 2: Results of the cluster analysis on zero-flow seasonality. Colours represent seasonality of zero-flow events. Blue colour denotes stations with zero-flow events observed from November to January. Red colour indicates zero-flow events in summer while green colour in the period between January and March
Figure 3: Significant increasing (later date) or decreasing (earlier date) trends in the mean date of zero-flow day occurrence, at the 10% significance level
Figure 4: Significant increasing (red triangle up) or decreasing (blue triangle down) trends, at the 10% significance level, for the annual or seasonal mean number of zero flow days (left), the annual or seasonal maximum length of dry spells (right)
Figure 5: Relative number of significant correlations at the 5% level between annual, summer and winter sum of zero flow days, and maximum length of dry periods with SPEI6, SPEI12, SPEI18 and SPEI24
Figure 6: Map of the significant correlations between the annual sum of zero flow days (top) and annual maximum length of zero flow days (bottom) with the SPEI18. The black crosses indicate stations where the correlation is not significant at the 10% level. Correlations are negative because the smaller the SPEI (water deficit), the larger the number of zero-flow days.
Figure 7: Correlations between the summer sum of zero-flow days and summer AMO (left), and the correlation between the winter sum of zero-flow days with winter NAO (right)