Maps of monthly self-calibrating Palmer Drought Severity Index (scPDSI) have been calculated for the period 1901-2002 for Europe (35N-70N and 10W-60E) with a spatial resolution of 0.5 x 0.5 degree. The recently introduced scPDSI is a convenient means of describing the spatial and temporal variability of moisture availability and is based on the more ommon Palmer Drought Severity Index. The scPDSI improves upon the Palmer Drought Severity Index by maintaining a consistent behaviour of the index
over diverse climatological regions. This makes spatial comparisons of scPDSI values on continental scales more meaningful.
Over the region as a whole, the mid-1940s to early 1950s stand out as a persistent and exceptionally dry period, whereas the mid-1910s and
late 1970s to early 1980s were very wet. The driest and wettest summers on record, in terms of the amplitude of the index averaged over Europe, were 1947 and 1915 respectively, while the years 1921 and 1981 saw over 11% and over 7% of Europe suffering from extreme drought or wet conditions respectively.
Trends in summer moisture availability over Europe for the 1901-2002 period fail to be statistically significant, both in terms of spatial means of the drought index and in the area affected by drought.
Moreover, evidence for widespread and unusual drying in European regions over the last few decades is not supported by the current work.
G van der Schrier, KR Briffa, PD Jones, TJ Osborn. Summer moisture variability across Europe
published, J. Climate, 2006, 19