Articles | Volume 21, issue 12
Research article
05 Dec 2017
Research article |  | 05 Dec 2017

Performance of the METRIC model in estimating evapotranspiration fluxes over an irrigated field in Saudi Arabia using Landsat-8 images

Rangaswamy Madugundu, Khalid A. Al-Gaadi, ElKamil Tola, Abdalhaleem A. Hassaballa, and Virupakshagouda C. Patil

Abstract. Accurate estimation of evapotranspiration (ET) is essential for hydrological modeling and efficient crop water management in hyper-arid climates. In this study, we applied the METRIC algorithm on Landsat-8 images, acquired from June to October 2013, for the mapping of ET of a 50 ha center-pivot irrigated alfalfa field in the eastern region of Saudi Arabia. The METRIC-estimated energy balance components and ET were evaluated against the data provided by an eddy covariance (EC) flux tower installed in the field. Results indicated that the METRIC algorithm provided accurate ET estimates over the study area, with RMSE values of 0.13 and 4.15 mm d−1. The METRIC algorithm was observed to perform better in full canopy conditions compared to partial canopy conditions. On average, the METRIC algorithm overestimated the hourly ET by 6.6 % in comparison to the EC measurements; however, the daily ET was underestimated by 4.2 %.

Short summary
In view of the pressing need to assess the productivity of agricultural fields in Saudi Arabia, this study was undertaken in an attempt to apply the METRIC model with Landsat-8 imagery for the determination of spatial and temporal variability in ET aiming at optimizing the quantification of crop water requirement and the formulation of efficient irrigation schedules. This paper will be of great interest to readers in the areas of agriculture (in general), water management and remote sensing.