Fig. 3: The 2019–2022 drought from a daily perspective: exceptionality and spatial extend.
a Time series of the R-index (red line, left y-axis) and of the two sub-indexes: mean anomaly (yellow line, left y-axis) and spatial extent (lilac shade, right y-axis) for the 2019–2022 drought in CESA (for more information see the “Methods” section). The black line depicts the 2.5th percentile of the R-index considering all the analysis period from ERA5-land dataset (1951–2022). The red filled dots identify the nine most extreme peaks of low R-index levels observed during the 4-yr period. The red numbers rank the peaks according to their intensity. The ones out of brackets show the rankings only considering the R-index levels obtained during the 4-year drought period, while the numbers inside brackets consider the R-index levels for all the analysis period. b Daily temporal evolution of the spatial extend (in \({10}^{2}{{km}}^{2}\)) of areas within CESA experiencing record-breaking low soil moisture anomalies, computed for several time-scales by applying a running mean filter with time windows between 1-day and 365-day. c Three-dimensional framework showing the location of the grid-points within CESA that observed daily negative soil moisture anomalies higher than two standard deviations during each of the nine extreme peaks of the R-index.
