High-resolution drought simulations and comparison to soil moisture observations in Germany

[摘要] Germany's 2018–2020 consecutive drought events resulted in multiple sectors – including agriculture, forestry, water management, energyproduction, and transport – being impacted. High-resolution information systems are key to preparedness for such extreme drought events. This study evaluates the newsetup of the one-kilometer German drought monitor (GDM), which is based on daily soil moisture (SM) simulations from the mesoscale hydrologicalmodel (mHM). The simulated SM is compared against a set of diverse observations from single profile measurements, spatially distributed sensornetworks, cosmic-ray neutron stations, and lysimeters at 40 sites in Germany. Our results show that the agreement of simulated and observedSM dynamics in the upper soil (0–25  cm ) are especially high in the vegetative active period (0.84 median correlation  R ) and lower inwinter (0.59 median  R ). The lower agreement in winter results from methodological uncertainties in both simulations and observations. Moderate butsignificant improvements between the coarser 4  km  resolution setup and the ≈  1.2  km resolution GDM in the agreement toobserved SM dynamics is observed in autumn ( + 0.07 median  R ) and winter ( + 0.12 median  R ). Both model setups display similar correlations toobservations in the dry anomaly spectrum, with higher overall agreement of simulations to observations with a larger spatial footprint. The higherresolution of the second GDM version allows for a more detailed representation of the spatial variability of SM, which is particularly beneficialfor local risk assessments. Furthermore, the results underline that nationwide drought information systems depend both on appropriate simulations ofthe water cycle and a broad, high-quality, observational soil moisture database.

[学科分类] 妇产科学