Effects of hysteresis and temporal variability in meteorological input data in modeling of solute transport in unsaturated soil using HYDRUS-1D / Effekten av hysteresis och tidsupplösning av meteorologiska indata på modellering av föroreningstransport i den omättade zonen med HYDRUS-1D
A one-dimensional, unsaturated transport model was used to simulate non-reactive transport of solutes. The effects of soil water hysteresis, and temporal variability in precipitation and evapotranspiration input data were evaluated. Simulations were conducted in HYDRUS-1D code for the period 1996–2008 for three different geographic locations in Sweden and for three different soil textures. Simulations were run for the period from March to September for both hysteretic and non-hysteretic cases with different temporal variability of precipitation and evapotranspiration input data (half-hourly, hourly, 2-hours, 4-hours, and daily). The results show that under non-hysteretic water flow solute migration is faster. Analysis of the downward migration of the solutes indicates that the effect of hysteresis is more pronounced in the coarse textured soils. The simulations show that a lower temporal resolution of the meteorological input data increases both underestimation of the downward movement of the solutes for non-hysteretic simulations and overestimation for hysteretic ones. Meanwhile, in most cases, this over and underestimation rises with increasing hydraulic conductivity of the soil. Finally, analysis of the results displays that the differences between hysteretic and non-hysteretic simulations are negligible when using daily input data.