- 1Czech Technical University in Prague, Faculty of Civil Engineering, Department of Landscape Water Conservation, Prague, Czechia (raquel.nogueira.rizzotto.falcao@fsv.cvut.cz)
- 2Soil Science and Geomorphology, Department of Geoscience, University of Tübingen, Rümelinstrasse 19–23, 72070 Tübingen, Germany
Rainfall simulators are indispensable in soil hydrology and erosion research, offering controlled conditions to investigate water erosion. Despite their widespread use, the absence of standardized methodologies leads to variability in design and rainfall characteristics across simulators. To address this challenge, key parameters such as drop size distribution and terminal velocity, uniformity of the spatial distribution of raindrops over the sprinkled surface area (Christiansen uniformity coefficient; CU), kinetic energy (KE), and rainfall intensity are used for comparative analysis. In this study, three rainfall simulators with varying transportability, nozzle system, and raindrop generation are compared. Laser distrometers and Tübingen Splash Cups (T-cups) were used to measure rainfall characteristics and kinetic energy.
The rainfall simulators produced rainfall intensity ranging from 38 to 95 mm h-1, and CU values between 60.5% and 75.8%. Most drops (>90%) were slower than 3.4 m s-1 for all simulations. The maximum number of drops was within the 0.25 – 0.375 mm class, generally smaller than that observed in natural rain, all at 1.4-1.8 m s-1 velocity. We found kinetic energy measured by T-cups to agree with values calculated with the Thies disdrometers, confirming its pertinence in rainfall studies. However, caution is advised when applying the T-cup equation under low kinetic energy scenarios, as it tends to overestimate KE.
Furthermore, we found that portable systems have distinct lower kinetic energy characteristics than indoor systems, and notable differences do not allow for the direct comparison of measurements. However, they have distinct advantages in direct field measurements and handling. The devices’ CU ranges from 60.5 to 75.8%, which falls within the range of those presented in the literature.
This study highlights the importance of accurately characterizing rainfall parameters before soil erosion modeling. The methodologies and insights provided tools for improved assessment of soil erosion risks, particularly considering its practicality in remote areas.
Keywords: Rainfall simulators, Soil erosion, Drop size distribution, Drop velocity, Raindrop kinetic energy
Research has been supported by project TUDI (European Union's Horizon 2020 research and innovation programme under grant agreement No 101000224), technology Agency of the Czech Republic (grants 8J23DE006 and QK22010261) and Czech Technical University in Prague (grant SGS23/155/OHK1/3T/11)
How to cite: Falcao, R., Krasa, J., Neumann, M., Kubát, J.-F., Gall, C., Seitz, S., and Dostal, T.: Evaluating Compact Portable and Indoor Rainfall Simulators for the Estimation of Rainfall Characteristics in Soil Erosion Studies, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6127, 2025.
How to cite: Falcao, R., Krasa, J., Neumann, M., Kubát, J.-F., Gall, C., Seitz, S., and Dostal, T.: Evaluating Compact Portable and Indoor Rainfall Simulators for the Estimation of Rainfall Characteristics in Soil Erosion Studies, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6127, https://doi.org/10.5194/egusphere-egu25-6127, 2025.
