Exploring the added value of a long-term multidisciplinary dataset in drought research - a drought catalogue for southwestern Germany dating back to 1801

Droughts are multidimensional hazards that can lead to substantial negative environmental, societal and economic impacts. To understand drought processes, multiple perspectives need to be considered. Numerous studies have investigated drought propagation from meteorological droughts via soil moisture to hydrological droughts. Regional variation in drought regimes and anthropogenic influences make it difficult to find a direct connection between the multiple aspects of drought. Additionally, the lack of a comprehensive long-term multi data compilation limits our understanding of the severity and frequency of current drought events and therefore drought risk management strategies.

This study developed a multidisciplinary long-term dataset of drought indices and impact records in southwestern Germany for the time period between 1800 and 2018. It is based on meteorological data, streamflow records and tree-ring data as well as reported information on drought impacts. Drought events were classified into moderate, severe and extreme events based on each datatype separately, leading to a regional drought catalogue. Within this catalogue, 22 extreme drought events were identified as common events among different archives and data types. Ranking the ten most severe droughts per indicator uncovers extreme events in the 19th century. However the development of drought frequency and severity over the last two centuries highlights a unique intensification of drought events in the 21st century.

The multidisciplinary approach provides new insights into similarities but also unique aspects of different drought indicators. The catalogue identifies and includes numerous drought events of the past, which can be used for further risk related analysis as well as for planning and management of future events.