ABSTRACT
In this study, the surface energy balance algorithm for land (SEBAL) model is used for estimation of evapotranspiration (ET) by the application of satellite RS. These estimates are validated against a lysimeter at the Water Technology Centre (WTC) experimental field within the Indian Agricultural Research Institute (IARI) farmland, New Delhi. SEBAL model is based on the evaporative fraction concept, and it has been applied to LANDSAT 1747-ETM+ (30 m resolution) data acquired over the IARI farmland. Daily ET from SEBAL was compared with observed ET.
Comparison with a lysimeter showed an RMSE of 0.14 mm d−1, indicating a good performance using the present approach. The crop-growing period from (the SEBAL model exhibited an R 2 of 0.91, R-RMSE of 0.063 mm d−1, PBIAS of 5.60, Mean Absolute Error (MAE) of 0.11), almost negligible Normalized Root Mean Square Error (NRMSE) and NSE, and d of 1. These validation studies indicate that remote sensing observations of ET provide a good comparison with ground-based stations for a nonstress wheat crop in the WTC field. The methodology described in the present study can be applied to remote areas of agricultural land where ground-based data are not possible.
