Droughts in western Central Europe and associated atmospheric circulation patterns since 1844

Abstract. Droughts in western Central Europe have major impacts on agriculture, ecosystems, and society, yet their long-term variability and drivers remain poorly understood. This study investigates drought variability over the past 180 years and its link to atmospheric circulation to identify their dynamic drivers. Three reanalysis datasets (ERA5, 20CRv3, and ModE-RA) are used to detect meteorological drought events via the 3-month Standardized Precipitation (Evapotranspiration) Indexes (SPI-3 & SPEI-3) and to connect them to atmospheric circulation patterns through k-means clustering. Dataset reliability is assessed over western Central Europe, providing consistent coverage from 70 to 165 years. Results show that recent severe and successive droughts, such as the 2018-drought, have historical precedents and display strong multidecadal variability. Diverging trends between SPI-3 and SPEI-3 over the last decades indicate an increasing role of atmospheric evaporative demand (AED). Summer dryness has intensified over the past 180 years, whereas winter dryness has declined. Regional and seasonal contrasts further emphasize the complexity of drought dynamics. Four distinct circulation patterns associated with droughts are identified: the Baltic High, British Isles High, North–South Dipole, and European High. Over time, droughts have become increasingly linked to the European High, a pattern characterized by strong AED anomalies, intense droughts, and this had a central role in the recent spring drying. The findings highlight the recent emergence of circulation patterns that enhance AED, marking a shift in the dynamic drivers of regional droughts under climate change.