Development of a Numerical Model for Evaluating the Effect of Litter Layer on Evaporation

A numerical model (LITEM) to evaluate the effect of the litter layer on evaporation was developed and used to estimate evaporation, soil temperature and soil water content. This model includes a sub-model to estimate the resistance of the litter layer to evaporation with its thickness and volumetric water content. The resistance of the litter layer to evaporation increases as volumetric water content of the litter layer decreases and as its thickness increases. Evaporation data in a deciduous broad-leaved forest measured using microlysimeter was simulated by the LITEM. The simulation showed good agreement with the measurement, and sound performance of the sub-model in simulation was also certified. According to the measurement for 2 days, evaporation from soil of 1.5 cm and 2 cm litter layers to that from bare soil was reduced to 47% and 61%, respectively. Loss of soil water content in three soils (bare soil, 1.5 cm litter layer and 2 cm litter layer) by evaporation was simulated by the LITEM, and the LITEM reasonably expressed the trend of volumetric soil water content. The simulated soil temperatures also showed good agreement with the field data.