A drought monitoring and forecasting system for Switzerland

The intensity and frequency of dry spells in Switzerland have increased in recent years and are likely to intensify in the future. Meanwhile, increases in water use and competition between different actors also place a greater pressure on existing water resources. Because drought has been identified as one of the main risks for various economic sectors in Switzerland, a unified monitoring and forecasting system is to be established through the joint efforts of three different agencies (federal offices for environment, meteorology and climatology, and topography). The project also includes contributions from Swiss research institutions and actively involves stakeholders in its development.

In this contribution, we introduce the Swiss national drought project with a particular focus on in situ and satellite-based monitoring and its integration with long-term forecasts. Current efforts include the creation of a national in situ soil moisture monitoring network with approximately 30 stations, the  development of meteorological and agricultural drought products and indices, as well as the establishment of near real time, downscaled, sub-seasonal forecasts derived from existing systems (local area model, IFS-ENS-EXT). Integrating these highly heterogeneous data streams into seamless products ranging from historical data to sub-seasonal forecasts, all within a consistent climatological baseline, is expected to represent both a major technical challenge but also a significant step forward that will greatly benefit downstream user applications. This meteorological basis will directly feed into impact-relevant drought indices and hydrological models, with the aim of better supporting an early warning system that has to take in consideration the needs of a very diverse user community, such as hydropower production, fluvial navigation, agriculture, forestry, or artificial snow production.