Abstract
Modeling soil water evaporation and soil moisture are valuable for many applications in diverse disciplines. Ritchie and Snyder, presented different models to estimate soil water evaporation (ES) rate. The former also simulates the soil water dynamics at different soil depths. The objectives of this study were to evaluate the potential use of the S2000 model for soils with water content above θDUL in some parts of the profile and to evaluate R2009 ES model and compare its performance with that of S2000. The study was carried out at the University of Florida Indian River Research and Education Center in Fort Pierce, Florida in 2012 and 2013. Eight Time-Domain Transmissometry (TDT) probes were installed in a lysimeter filled with sand and measured hourly soil water content for six months. Three drying cycles (cases) were used for the evaluation of the models. R2009 underestimated the soil water content near the soil surface for Case 1 and 2. While for Case 3, R2009 estimated the near surface soil water content well for the first four days and then it tended to underestimate for the rest of the days. S2000 with the proper parameterization outperformed R2009 which overestimated ES. It was evident that getting the suitable parameterization for S2000 model was not always guaranteed. These finding may only apply for sandy soils similar to the one used in this study. Future studies should be done on different soils and diverse environment before generalization can be made.
Highlights
Evapotranspiration (ET) is a major component of the energy and water balances over land
Water evaporation from a soil surface can be divided into two stages: (i) the constant-rate stage in which ES is limited only by the supply of energy to the surface, and (ii) the falling-rate stage in which water movement to the evaporation sites near the surface is controlled by the soil moisture conditions and soil hydraulic properties [3,4]
This indicated that F is somewhat dependent on the initial soil water content which was higher for these soil depths in Case 3 than Case 1 which was greater than Case 2
Summary
Evapotranspiration (ET) is a major component of the energy and water balances over land. Evaporation of water from soil surfaces (ES) is a major component in the soil water balance for field crops with incomplete cover and for bare soil conditions. Hydrology, and water quality models require the simulation of evaporation from the soil surface. Quantification of ES is necessary in evaluating the water balance of soils for use in environmental and hydrologic studies and for crop management. Water evaporation from a soil surface can be divided into two stages: (i) the constant-rate stage in which ES is limited only by the supply of energy to the surface, and (ii) the falling-rate stage in which water movement to the evaporation sites near the surface is controlled by the soil moisture conditions and soil hydraulic properties [3,4]
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