Comparing actual evapotranspiration estimations by METRIC to in-situ water balance measurements over an irrigated field in Turkey

ABSTRACT Estimating actual evapotranspiration (ETa) rates in large-scale irrigation schemes is of great importance to improve water use efficiency. Crop types can be determined by employing remote sensing techniques coupled with ground truth data. This study aimed to: (a) conduct a water balance study by making in-situ water balance measurements, (b) derive cropping pattern maps, (c) acquire crop evapotranspiration (ETc), (d) generate fully distributed ETa maps, and (e) compare ETa estimations with ETc and in-situ water balance. Landsat 7 and 8 satellite data, and meteorological data were used to estimate ETa in the Eastern Mediterranean Region of Turkey in the 2021 hydrological year. Crop types were classified using Sentinel 2A–2B satellite images. The change in catchment storage was +67.08 mm with a 3.34% water balance closure error. The correlation between ETa and ETc for irrigated wheat, potato, lettuce, corn-1, peanut-1, soybean-2, and citrus was significant in the growing season.