Mona Asarehmostaghim - MSc Irrigation and Drainage Engineer of Tehran University and Expert of Yekom Consulting Engineers
Ali Rahimikhoob - Assistant professor, Irrigation and Drainage Engineering Department, collage of Abureyhan, University of Tehran
Lena Asarehmostaghim - M.Sc student Civil Engineering- Geotechnique of Shahid Chamran University

Understanding potential evapotranspiration (ETo) widely used in hydrology and is essential for agriculture water resource. Unfortunately, some weather variables, is often missing which could impede the estimation of ETo. Since, the objective of this study was to examine whether it is possible to attain the rellable estimation of ETo by empirical model and satellite data for daily time step. This objective was reached by the evaluation of the reliability of Thornthwaite empirical model by Land Surface Tempeture (LST) (as an alternative input) obtained from AVHRR sensor, as compared to the Penman-Monteith method (PM). The five Suger cane field selected for this study are located in semi-arid environment in the Khuzestan (in the south west of Iran). 238 satellite images during 2004-2009 without cloud were selected to estimating LST. Results showed that the Thornthwaite model using NOAA/AVHRR data is the appropriate for this particular study area, with RMSE of 1.3 mmd-1, and a correlation of 0.82. these results suggest that using satellite-sensed LST improve ETo estimates for area where climate data are not available.

Remote sensing, LST, Evapotranspiration, Thornthwaite, Suger cane field