Estimation of Actual Evapotranspiration Using Soil Moisture Balance and Remote Sensing

Determination of actual evapotranspiration is an important step for simulating the crop growth models in agricultural decision-making process. In this study, actual evapotranspiration (ETa) values for the main crops cultivated in Shahrekord plain, Chaharmahal and Bakhtiari province, Iran, are estimated based on real-time modeling and compared with the results obtained from the remote sensing data. Soil moisture balance was simulated considering the variation rate of crop canopy cover and its effects on evaporation and transpiration parameters. Daily values of ETa were predicted in a repeatable cycle based on the available soil moisture in root zone. Moreover, remote sensing images were analyzed as a data source to achieve the crop water requirement in critical times. For this objective, surface energy balance algorithm for land (SEBAL) was used to characterize the evapotranspiration and then derived ETa. Preliminary results obtained by applying satellite information showed a good agreement between the SEBAL estimates of evapotranspiration fluxes and the corresponding values simulated by the soil moisture estimation technique.

Automated summary

The study estimated actual evapotranspiration values for main crops in Shahrekord plain, Iran using real-time modeling and compared it with remote sensing data. Soil moisture balance was simulated considering crop canopy cover variation, and daily ETa values were predicted based on available soil moisture in the root zone. Remote sensing images were analyzed to determine crop water requirement at critical times, showing good agreement with results obtained through soil moisture estimation techniques.