Spatiotemporal Distribution of Calibration Coefficients of Hargreaves Equation for Estimating Potential Evapotranspiration in Mainland China
文献类型： 外文期刊
作者： Long, Huaiyu 1 ; Shuai, Xiufu 2 ; Lei, Qiuliang 1 ; Zhang, Renlian 1 ;
作者机构： 1.Chinese Acad Agr Sci, Inst Agr Resources & Reg Planning, Natl Engn Lab Improving Qual Arable Land, Beijing 100081, Peoples R China
2.Univ Hawaii Manoa, Dept Geog, Honolulu, HI 96822 USA
3.Shanxi Acad Agr Sci, Inst Agr Environm & Resources, Taiyuan 030006, Shanxi Province, Peoples R China
关键词： Potential evapotranspiration;Penman-Monteith;Hargreaves;Mainland China
期刊名称：JOURNAL OF IRRIGATION AND DRAINAGE ENGINEERING-ASCE （ 影响因子：1.126； 五年影响因子：1.589 ）
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收录情况： SCI
摘要： It is important to calibrate the potential evapotranspiration measured by the Hargreaves method (ET0,HG) using the Penman-Monteith method (ET0,PM). However, the substantial temporal variations in the calibration coefficients (ET0 ratio measured by the two methods) have not been considered in the spatial analysis of the calibration coefficients. The objectives of this study were to investigate the spatiotemporal distribution of the calibration coefficient on the scale of Mainland China and to compare the accuracy of the calibrated ET0,HG by this spatiotemporal calibration method with three alternative methods including the calibration coefficients over space or time. One year was divided into 72 five-day periods in this study. For each five-day period, quantitative models were used to describe the spatial dependence of the calibration coefficients, and the maps of the calibration coefficients were produced by the Kriging method. The accuracies of the calibrated ET0 by this spatiotemporal calibration method and the other three methods were evaluated by criteria such as absolute bias, relative bias, root mean square error, and mean bias error. The results showed spatiotemporal changes in the parameters of the geostatistical models and the maps of the calibration coefficients of Mainland China. The maps were characterized by their divisions into two regions along a calibration coefficient contour of 1.0, and the directions of these contours showed obvious seasonal changes. The accuracy of the calibrated ET0,HG was highest when both the spatial and temporal variations of the calibration coefficients were considered simultaneously. DOI: 10.1061/(ASCE)IR.1943-4774.0000534
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