Estimation of Evaporation from Drying Soil Column with Different Initial Soil Water Content by Maximum Soil Surface Temperature

Abstract

Modifying Ben-Asher's model, a simple model to estimate evaporation using only maximum and minimum surface temperature (MST) was proposed based on energy balance on the ground surface and supposing periodic sinusoidal change in soil surface temperature. Non-saline and saline soil (Silty loam) columns were adjusted at initial moisture condition between air dry to field water capacity. Daily evaporation (E_d) and soil temperature of the columns were measured for 23 days under field condition. At higher water content above 15 % and 19 % for non-saline loam and saline loam, respectively, the observed evaporation (E_{d obs.}) and estimated evaporation (E_{d est.}) were in a good agreement. However, the MST model overestimated evaporation at lower water content. Evaporation from the saline loam was somewhat smaller than that of the non-saline loam. The MST model can apply to estimate evaporation over a large scale area under wet conditions, if it would be combined with an infrared satellite image.