Evaluation of a remote sensing-based dual crop coefficient approach for estimation of separated amounts of evaporation and transpiration

The accuracy of the classical methods to calculate evapotranspiration of plants for use in large areas may not be sufficient and therefore less useful. Thus, the choice of high-precision approaches, despite of restrictions ahead seems necessary. The purpose of this study is calculation of sugarcane evapotranspiration in Ahvaz, Khuzestan province using two methods. In method one, soil evaporation and crop transpiration were separately calculated using NDVI index extracted from MODIS images in. In the second approach, evapotranspiration was estimated using single crop coefficient approach known as FAO 56 method using available coefficients. Besides, crop coefficient values were calculated using SimDualKc software during entire growing season and FAO Penman-Monteith equation was worked out accordingly.The results were also compared to a lysimetric dataset. Correlation coefficient of ET estimations using single and dual crop coefficient approaches with lysimetric measurements were 0.954 and 0.885, respectively. A. On the other hand, the standard error for single coefficient approach was 67.29 and 29.34 dual approach. The results showed that the remote sensing-based dual coefficient approach provides acceptable estimations of sugar cane in the region. More studies are recommended for further scrutiny.