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A Lagrangian model for soil water dynamics during rainfall-driven conditions

Zehe, Erwin; Jackisch, Conrad

Abstract (englisch):
Within this study we propose a stochastic approach to simulate soil water dynamics in the unsaturated zone by using a non-linear, space domain random walk of water particles. Soil water is represented by particles of constant mass, which travel according to the Itô form of the Fokker–Planck equation. The model concept builds on established soil physics by estimating the drift velocity and the diffusion term based on the soil water characteristics. A naive random walk, which assumes all water particles to move at the same drift velocity and diffusivity, overestimated depletion of soil moisture gradients compared to a Richards solver. This is because soil water and hence the corresponding water particles in smaller pore size fractions are, due to the non-linear decrease in soil hydraulic conductivity with decreasing soil moisture, much less mobile. After accounting for this subscale variability in particle mobility, the particle model and a Richards solver performed highly similarly during simulated wetting and drying circles in three distinctly different soils. Both models were in very good accordance during rainfall-driven condition ... mehr


Zugehörige Institution(en) am KIT Institut für Wasser und Gewässerentwicklung (IWG)
Publikationstyp Zeitschriftenaufsatz
Jahr 2016
Sprache Englisch
Identifikator DOI: 10.5194/hess-20-3511-2016
ISSN: 1027-5606, 1607-7938
URN: urn:nbn:de:swb:90-593970
KITopen ID: 1000059397
Erschienen in Hydrology and earth system sciences
Band 20
Heft 9
Seiten 3511-3526
Lizenz CC BY 3.0 DE: Creative Commons Namensnennung 3.0 Deutschland
Bemerkung zur Veröffentlichung Gefördert durch den KIT-Publikationsfonds
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