Real-time crop coefficient from SEBAL method for estimating the evapotranspiration

Islam Abou El-Magd

doi:10.1117/12.510664

24 February 2004 Real-time crop coefficient from SEBAL method for estimating the evapotranspiration

Islam Abou El-Magd

Proceedings Volume 5232, Remote Sensing for Agriculture, Ecosystems, and Hydrology V; (2004) https://doi.org/10.1117/12.510664
Event: Remote Sensing, 2003, Barcelona, Spain

Abstract

Crop coefficients (K_c) are defined as the ratio of actual crop evapotranspiration to the evapotranspiration (Et_o) of a grass reference crop, often taken from Penman/Monteith’s methodology. They are used to estimate theoretical crop evapotranspiration (Et_c). Actual evapotranspiration is measured in field lysimeters but this lacks acceptability when applied to the field or large irrigation schemes where conditions are very variable. This paper uses the SEBAL method (Bastiaanssen et al., 1998) to determine actual evapotranspiration from satellite images. This is compared with estimated Et_o from both Penman/Monteiths methodology and Et_o estimated from a SEBAL estimation of reference crop evaporation within a project. The range of K_c values for the cotton crop were then calculated. Crop coefficient K_c maps were made for two irrigation projects. The methodology was applied on a large cotton irrigation scheme (Starikan) southern Kazakhstan. The estimated mean real time K_c value of 1.16 (±1-3% error) was higher than the standard K_c value of 1.1 identified by FAO-56. The methodology was validated on a different date and different irrigation schemes (Chardara) 200 km south Starikan. The methodology is discussed.

Citation Download Citation

Islam Abou El-Magd "Real-time crop coefficient from SEBAL method for estimating the evapotranspiration", Proc. SPIE 5232, Remote Sensing for Agriculture, Ecosystems, and Hydrology V, (24 February 2004); https://doi.org/10.1117/12.510664

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