Abstract
The 2018–2020 consecutive drought events in Germany resulted in impacts related with several sectors such as agriculture, forestry, water management, industry, energy production and transport. A major national operational drought information system is the German Drought Monitor (GDM), launched in 2014. It provides daily soil moisture (SM) simulated with the mesoscale hydrological model (mHM) and its related soil moisture index at a spatial resolution of 4 × 4 km2. Key to preparedness for extreme drought events are high-resolution information systems. The release of the new soil map BUEK200 allowed to increase the model resolution to ~1.2 × 1.2 km2, which is used in the second version of the GDM. In this paper, we explore the ability to provide drought information on the one-kilometer scale in Germany. Therefore, we compare simulated SM dynamics using homogenized and deseasonalized SM observations to evaluate the high-resolution drought simulations of the GDM. These SM observations are obtained from single profile measurements, spatially distributed sensor networks, cosmic-ray neutron stations and lysimeters at 40 sites in Germany. The results show that the agreement of simulated and observed SM dynamics is especially high in the vegetation period (0.84 median correlation R) and lower in winter (0.59 median R). Lower agreement in winter results from methodological uncertainties in simulations as well as in observations. Moderate but significant improvements between the first and second GDM version to observed SM were found in correlations for autumn (+0.07 median R) and winter (+0.12 median R). The annual drought intensity ranking and the spatial structure of drought events over the past 69 years is comparable for the two GDM versions. However, the higher resolution of the second GDM version allows a much more detailed representation of the spatial variability of SM, which is particularly beneficial for local risk assessments. Furthermore, the results underline that nationwide drought information systems depend both on appropriate simulations of the water cycle and a broad, high-quality observational soil moisture database.
Highlights
20 The extreme drought events since 2018 in Germany lead to multi-sectoral impacts (Madruga de Brito et al, 2020) and increased stakeholder awareness
The results show that the agreement of simulated and observed soil moisture (SM) dynamics is especially high in the vegetation period (0.84 median correlation R) and lower in winter (0.59 median R)
This study presents an evaluation of soil moisture (SM) dynamics from two mesoscale hydrological model (mHM) model simulations from operational German Drought Monitor (GDM) setups
Summary
20 The extreme drought events since 2018 in Germany lead to multi-sectoral impacts (Madruga de Brito et al, 2020) and increased stakeholder awareness. Recent studies emphasized that extreme soil moisture drought events will be more likely and more severe in Central Europe under future warming scenarios (Samaniego et al, 2018; Grillakis, 2019). The singularity of the 2018/19 drought within observational records in terms of consecutive multiyear water deficits was confirmed for Germany and Central Europe (Boergens et al, 2020; Hari et al, 2020). With these prospects comes an increased need for state-of-the-art.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
