Actual evapotranspiration estimation by Triangle algorithm and landsat8 data (case study: Mashhad plain-Khorasan Razavi province)

Subject Areas : Applications in water resources management

Mojdeh  Salimifard ¹ (The Ferdowsi University of Mashhad- Faculty of Agriculture- Department of water engineering)
Hosein  Sanaei nejad ² (Professor, Ferdowsi University of Mashhad Faculty of Agriculture- Department of water engineering)
Alireza  Rashki ³ (Associated Professor of Ferdowsi university-Department of desert and arid area management-Faculty of Natural Resource and Environment.)

Received: 2022-08-08 Accepted : 2022-10-01 Published : 2022-10-01

Keywords: Triangle algorithem, Actual Evapotranspiration, Landsat8, Mashhad Plain,

Abstract :

The estimation of spatially-variable actual evapotranspiration (AET) is a critical challenge to regional water resources management. Most of the available crop coefficient-based ET computation methods provide point-scale estimates which need up scaling to apply at the catchment or command area scale. A variety of remote sensing methods with varying complexity have been developed to generate regional AET estimates based on surface energy balance or vegetation status. The triangle method is used to estimate regional evapotranspiration (ET) in arid and semi-arid regions. In this study, for estimation, actual evapotranspiration was used Landsat 8 data in 2020 and triangle algorithm in Mashhad plain. The results of the triangle algorithm were verified with the evapotranspiration obtained from the FAO Penman-Monteith coupled crop coefficient in wheat and maize farms. The validation results showed high accuracy of the triangle algorithm in actual evapotranspiration estimation so that the correlation coefficient observed more than 0.7 and the maximum Root Mean Square Error (RMSE) and Mean Absolute Error (MAE) was 1.67 and 1.48 mm per day, respectively.