Performance Evaluation of Soil Heat Flux Models in Great Plains

Soil heat flux plays an important role in land surface energy dynamics by constraining the amount of available energy for partitioning between latent heat flux and sensible heat flux. Thus accurate quantification of the soil heat flux is of key importance in energy balance studies. In this study, the performances of four different methods have been evaluated for the soil heat flux estimation in maize and soybean fields under irrigated and dryland conditions. Statistical analysis of the model performance has shown a wide variation in the ability of these models from site to site and from year to year. The RMSE for irrigated maize ranged from 15.16 W m^–2 to 81.25 W m^–2, whereas the range for dryland maize was 14.99 W m^–2 to 55.81 W m^–2. The RMSE between predicted and measured soil heat flux for irrigated soybean was between 19.36 W m^–2 and 50.83 W m^–2. Relatively a narrow range (18.45–35.24 W m^–2) of RMSE was found for dryland soybean. In view of wide range of RMSE and negative model efficiency, it is recommended that the local calibration of the model should be carried out for remote estimation of soil heat flux.