Modeling bulk canopy resistance from climatic variables for predicting hourly evapotranspiration of maize and buckwheat

This study presents models for predicting hourly canopy resistance (r (c)) and evapotranspiration (ETc) based on Penman-Monteith approach. The micrometeorological data and ET (c) were observed during maize and buckwheat growing seasons in 2006 and 2009 in China and Japan, respectively. The proposed models of r (c) were developed by a climatic resistance (r (*)) that depends on climatic variables. Non-linear relationships between r (c) and r (*) were applied. The measured ETc using Bowen ratio energy balance method was applied for model validation. The statistical analysis showed that there were no significant differences between predicted ETc by proposed models and measured ETc for both maize and buckwheat crops. The model for predicting ETc at maize field showed better performance than predicting ETc at buckwheat field, the coefficients of determination were 0.92 and 0.84, respectively. The study provided an easy way for the application of Penman-Monteith equation with only general available meteorological database.