Modifying Hargreaves-Samani equation for estimating reference evapotranspiration in dryland regions of Amudarya River Basin

Reference evapotranspiration (ETo) is a key factor in determining the amount of water needed for crops, which is crucial to correct irrigation planning. FAO Penman-Monteith (EToPM) is among the most popular method to estimate ETo. Apparently sometimes it is difficult to compute ETo using Penman-Mont...

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Main Authors: Gafurov, Zafar, Eltazarov, Sarvarbek, Akramov, Bekzod, Yuldashev, Tulkun, Djumaboev, Kakhramon, Anarbekov, Oyture
Format: Journal Article
Language:Inglés
Published: Scientific Research Publishing, Inc. 2018
Subjects:
Online Access:https://hdl.handle.net/10568/105649
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author Gafurov, Zafar
Eltazarov, Sarvarbek
Akramov, Bekzod
Yuldashev, Tulkun
Djumaboev, Kakhramon
Anarbekov, Oyture
author_browse Akramov, Bekzod
Anarbekov, Oyture
Djumaboev, Kakhramon
Eltazarov, Sarvarbek
Gafurov, Zafar
Yuldashev, Tulkun
author_facet Gafurov, Zafar
Eltazarov, Sarvarbek
Akramov, Bekzod
Yuldashev, Tulkun
Djumaboev, Kakhramon
Anarbekov, Oyture
author_sort Gafurov, Zafar
collection Repository of Agricultural Research Outputs (CGSpace)
description Reference evapotranspiration (ETo) is a key factor in determining the amount of water needed for crops, which is crucial to correct irrigation planning. FAO Penman-Monteith (EToPM) is among the most popular method to estimate ETo. Apparently sometimes it is difficult to compute ETo using Penman-Monteith due to challenges on data availability. FAO Penman-Monteith method requires many parameters (solar radiation, air temperature, wind speed and humidity), while Hargreaves-Samani method calculates ETo based on air temperature. Because Central Asia is a data limited region with weather stations unable to provide all required parameters for the PM method, this study aimed to estimate ETo using the Hargreaves and Samani (HS) method in Karshi Steppe, in Kashkadarya province, in southern Uzbekistan, based on data from 2011 to 2017. Reference evapotranspiration calculated by non-modified HS method is underestimated during the summer months. The reason for this underestimation might be higher air temperature and wind speed during these months. Therefore, the HS method in its original form cannot be used in our study area to estimate ETo. Modification of the EToHS, through application of a bias correction factor, had better performance and allowed improving the accuracy of the ETo calculation for this region. The calculated ETo values can inform decision making and management practices regarding water allocation, irrigation scheduling and crop selection in dry land regions of Amudarya river basin and the greater Central Asia area.
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spelling CGSpace1056492023-07-03T07:48:37Z Modifying Hargreaves-Samani equation for estimating reference evapotranspiration in dryland regions of Amudarya River Basin Gafurov, Zafar Eltazarov, Sarvarbek Akramov, Bekzod Yuldashev, Tulkun Djumaboev, Kakhramon Anarbekov, Oyture river basins evapotranspiration estimation forecasting arid zones temperature irrigated land climatic factors statistical methods Reference evapotranspiration (ETo) is a key factor in determining the amount of water needed for crops, which is crucial to correct irrigation planning. FAO Penman-Monteith (EToPM) is among the most popular method to estimate ETo. Apparently sometimes it is difficult to compute ETo using Penman-Monteith due to challenges on data availability. FAO Penman-Monteith method requires many parameters (solar radiation, air temperature, wind speed and humidity), while Hargreaves-Samani method calculates ETo based on air temperature. Because Central Asia is a data limited region with weather stations unable to provide all required parameters for the PM method, this study aimed to estimate ETo using the Hargreaves and Samani (HS) method in Karshi Steppe, in Kashkadarya province, in southern Uzbekistan, based on data from 2011 to 2017. Reference evapotranspiration calculated by non-modified HS method is underestimated during the summer months. The reason for this underestimation might be higher air temperature and wind speed during these months. Therefore, the HS method in its original form cannot be used in our study area to estimate ETo. Modification of the EToHS, through application of a bias correction factor, had better performance and allowed improving the accuracy of the ETo calculation for this region. The calculated ETo values can inform decision making and management practices regarding water allocation, irrigation scheduling and crop selection in dry land regions of Amudarya river basin and the greater Central Asia area. 2018 2019-11-06T08:20:35Z 2019-11-06T08:20:35Z Journal Article https://hdl.handle.net/10568/105649 en Open Access Scientific Research Publishing, Inc. Gafurov, Zafar; Eltazarov, S.; Akramov, Bekzod; Yuldashev, Tulkun; Djumaboev, Kakhramon; Anarbekov, Oyture. 2018. Modifying Hargreaves-Samani equation for estimating reference evapotranspiration in dryland regions of Amudarya River Basin. Agricultural Sciences, 9(10):1354-1368. doi: 10.4236/as.2018.910094
spellingShingle river basins
evapotranspiration
estimation
forecasting
arid zones
temperature
irrigated land
climatic factors
statistical methods
Gafurov, Zafar
Eltazarov, Sarvarbek
Akramov, Bekzod
Yuldashev, Tulkun
Djumaboev, Kakhramon
Anarbekov, Oyture
Modifying Hargreaves-Samani equation for estimating reference evapotranspiration in dryland regions of Amudarya River Basin
title Modifying Hargreaves-Samani equation for estimating reference evapotranspiration in dryland regions of Amudarya River Basin
title_full Modifying Hargreaves-Samani equation for estimating reference evapotranspiration in dryland regions of Amudarya River Basin
title_fullStr Modifying Hargreaves-Samani equation for estimating reference evapotranspiration in dryland regions of Amudarya River Basin
title_full_unstemmed Modifying Hargreaves-Samani equation for estimating reference evapotranspiration in dryland regions of Amudarya River Basin
title_short Modifying Hargreaves-Samani equation for estimating reference evapotranspiration in dryland regions of Amudarya River Basin
title_sort modifying hargreaves samani equation for estimating reference evapotranspiration in dryland regions of amudarya river basin
topic river basins
evapotranspiration
estimation
forecasting
arid zones
temperature
irrigated land
climatic factors
statistical methods
url https://hdl.handle.net/10568/105649
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