Long-term variability and trends in meteorological droughts in Western Europe (1851-2018)

We analyzed long-term variability and trends in meteorological droughtsacross Western Europe using the Standardized Precipitation Index (SPI). Precipitationdata from 199 stations spanning the period 1851-2018 were employed, followinghomogenisation, to derive SPI-3 and SPI-12 series for each station, together withindices on drought duration and severity. Results reveal a general absence ofstatistically significant long-term trends in the study domain, with the exception ofsignificant trends at some stations, generally covering short periods. The largestdecreasing trends in SPI-3 (i.e. increasing drought conditions) were found for summerin the British and Irish Isles. In general, drought episodes experienced in the last two orthree decades have precedents during the last 170 years, emphasising the importance oflong records for assessing change. The main characteristic of drought variability inWestern Europe is its strong spatial diversity, with regions exhibiting a homogeneoustemporal evolution. Notably, the temporal variability of drought in Western Europe ismore dominant than long-term trends. This suggests that long-term drought trendscannot be confirmed in Western Europe using precipitation records alone. This studyprovides a long-term regional assessment of drought variability in Western Europe,which can contribute to better understanding of regional climate change during the past two centuries.