Volume 12, Issue 24 (9-2021)                   J Watershed Manage Res 2021, 12(24): 217-227 | Back to browse issues page


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Mahmudzadeh E, Anvari S. (2021). Sensitivity Analysis of SEBAL Algorithm for Estimating Agricultural Irrigation Requiremants. J Watershed Manage Res. 12(24), 217-227. doi:10.52547/jwmr.12.24.217
URL: http://jwmr.sanru.ac.ir/article-1-1097-en.html
Department of Ecology, Institute of Advanced Science and Technology and Environmental Sciences, University of Industrial and Advanced Technology, Kerman, Iran
Abstract:   (2933 Views)
Extended Abstract
Introduction and Objective: The accurate estimation of actual evapotranspiration (ETA), i.e. crop water requirements, is an important issue for irrigation water allocation at fields and improving water efficiency. In the present study, ETA for Sorghum crop was estimated using surface energy balance algorithm for land (SEBAL) and by employing Landsat8 satellite images; meteorological data and DEM map and then compared with the measured values of lysimeter.
Material and Methods: For carrying out the sensitivity analysis, the key parameters of SEBAL algorithm was altered at the range of ±10 , ±20 , ±30 , ±40  , ±50  and resultantly the variation of ETA corresponding to decrease and increase of these parameters was investigated. The changes of key parameters on the days of 206, 238 and 254, based on Julian days calendar, were evaluated at eight points with different vegetation densities. Albedo parameters have moderate to high sensitivity, so that the albedo parameter has medium and high sensitivity in the areas with ET> 10 and ET <10, respectively.
Results: The results of SEBAL showed the value of accuracy indices were acceptable at a significant level of 95%, while compared with those of lysimeter measurements. The results of the sensitivity analysis also showed the surface temperature and input shortwave radiation are more sensitive especially at the areas having low ETA values. The wind speed and
Conclusion: In general, in addition to high economic efficiency compared to other conventional methods, the SEBAL algorithm has a good efficiency in estimating ET. Also, performing sensitivity analysis and determining the key input parameters, while increasing the accuracy of measuring those parameters, can greatly improve the modeling results.
 
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Type of Study: Applicable | Subject: ساير موضوعات وابسته به مديريت حوزه آبخيز
Received: 2020/07/20 | Revised: 2022/02/23 | Accepted: 2020/10/5 | Published: 2021/09/1

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