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A monthly regression correction model for the Hargreaves–Samani method in Mainland China
Author(s) -
Xia Xingsheng,
Zhu Xiufang,
Pan Yaozhong,
Zhang Jinshui
Publication year - 2020
Publication title -
irrigation and drainage
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.421
H-Index - 38
eISSN - 1531-0361
pISSN - 1531-0353
DOI - 10.1002/ird.2445
Subject(s) - linear regression , evapotranspiration , regression analysis , regression , environmental science , statistics , mainland china , mathematics , coefficient of determination , standard error , climatology , geography , china , ecology , archaeology , geology , biology
Reference crop evapotranspiration (ET 0 ) is an important parameter for irrigation engineering. It can be calculated using the Penman–Monteith method (PM), which results in ET 0‐PM . This study uses ET 0‐PM to determine the availability of a monthly linear regression correction model for the Hargreaves–Samani method (HG). The data were obtained from 647 meteorological stations in mainland China, which are contained within the data set of monthly values of climate data from Chinese surface stations. For most stations, the correlation coefficient of ET 0‐PM and ET 0‐HG (determined by the HG method) ranges from 0.5 to 1.0. This provides the necessary conditions for the monthly linear regression correction of ET 0‐HG . The mean relative change of the mean absolute error before and after the ET 0‐HG correction for each year indicates that the scheme adopted in this study yields improved correction results during autumn, winter and spring in mainland China and poor results during summer. However, the monthly regression correction model for the HG is only available for part of the stations in each season. This study supplements a case for the larger‐scale ET 0‐HG monthly regression correction. This can be a reference for the further refinement of the ET 0‐HG spatio‐temporal correction © 2020 John Wiley & Sons, Ltd.