Narongrit, C, Chankao, K (2009). Development and validation of rice evapotranspiration model based on Terra/MODIS remotely sensed data. JOURNAL OF FOOD AGRICULTURE & ENVIRONMENT, 7(4-Mar), 684-689.
The simple model was developed to estimate daily evapotranspiration (ET) by using Terra-MODIS remotely sensed data. The satellite ET model was based on the Hargreaves model which requires only two climatic variables; temperature and incident solar radiation. By using the satellite ET model, temperature in terms of LSTRS was directly calculated from brightness temperatures of MODIS channels 31 and 32; while incident solar radiation in terms of APAR(RS) was calculated from NDVIRS computed from reflectance of MODIS channels 1 and 2. ET calibrated from the model was experimented to assess sensitivity of ET on rice grown under increased temperature (2 degrees C.) The results showed that modeled ET had a good agreement with Penman-based ET, a typical model widely used for estimating irrigated water supply. ETRS models showed a better correlation with LSTRS' compared to that with NDVIRS. The experimental pots results showed that ET amount based on developed model was sufficient for water consumption of rice. ET computed from the model ranged from 3.43 to 5.56 mm/day. However, from rice's height and leaf area growth data, it was found that the optimal amount of water supply was between 3.65-4.57 mm/day, indicating 6-17% error of the developed model.