A comparison of actual evapotranspiration estimates based on Remote Sensing approaches with a classical climate data driven method

Soghra Tofigh,Dariush Rahimi,Reza Zakerinejad

doi:10.14712/23361980.2020.12

Abstract

The knowledge of actual evapotranspiration at farm level is a prerequisite for irrigation planning, farm management, to increase production and reduce water consumption. To accomplish this, comprehensive and accurate assessment methods should be applied. In order to evaluate accurately evapotranspiration processes we compared lysimeter evapotranspiration data with MODIS (Aqua and Terra satellites) and LANDSAT (SEBAL algorithm) satellite images as well as with the FAO Penman-Montith method. The findings indicate the low error rate, high correlation (1) and appropriateness of SEBAL in estimating actual evapotranspiration. The error values MAD, MSE and RMSE between lysimeter and the SEBAL algorithm were 0.59, 0.36 and 0.60 respectively. The second best performance was established for the FAO Penman-Montith method. The obtained error values MAD, MSE and RMSE between the lysimeter and FAO-Penman-Montith method are 0.91, 1.29 and 1.13, respectively.

Highlights

Water need is one of the most important parameters in crop cultivation and in terms of planning the irrigation calendar
The data bases consist of three data groups: i) meteorological data collected from Farokhshahr station which include average, minimum and maximum temperature, average, minimum and maximum precipitation, relative humidity (RH), wind speed, sunny hours, ii) evapotranspiration data measured by the lysimeter, iii) Landsat satellite images (2016–2017), and vi) the MODIS evapotranspiration product (2016–2017) Table 1
In total the Chaharmahal and Bakhtiari province is covered by circa 248,000 hectares of agricultural land, 79,854 hectares of these are located in the Shahrekord plain, of which, 58,553 hectares are under irrigation cultivation and 21,301 hectares are under rain fed cultivation

Summary

Introduction

Water need is one of the most important parameters in crop cultivation and in terms of planning the irrigation calendar. Water Source deficit estimations are one of the major challenges in dry and semi-arid regions like Iran which is due to the low amount of precipitation (248 mm), high temperatures (average temperature 18 °C, which is 3 °C higher than the global average) long dry season (in some areas up to 8 months), high evaporation, inappropriate cultivation pattern and irregular irrigation methods (Alizadeh 2016; Zakerinejad and Masoudi 2019). Due to the high impact of evapotranspiration processes in plant and water resources management we assess different models for the Iranian conditions. Different methods exist on the marked such as: direct measurements (Lysimeter), multiple models like Priestley-Taylor, Jensen-Haise, ThornthWaite, Blaney-Criddle, FAO-Pennman Monteith, Hargreaves-Samani, Turc, Making and Ritchie (Allen et al 1998; Zare Haghi et al 2016). The MODIS sensor measures evapotranspiration, that is represented in a 8-day composite dataset

Methods

Results

Conclusion