中国大陆地区基于太阳辐射经验值计算ET<sub>0</sub>的适用性研究

夏兴生; 朱秀芳; 潘耀忠; 张锦水

Applicability of the empirical value of solar radiation in estimation of ET₀ in Mainland China

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DOI：10.7606/j.issn.1000-7601.2019.06.32

Key Words: Penman-Monteith formula solar radiation reference crop evapotranspiration difference analysis China

Author Name	Affiliation
XIA Xingsheng	State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing and Digital Earth of Chinese Academy of Sciences, Beijing 100875, China Institute of Remote Sensing Science and Engineering, Faculty of Geographical Science,Beijing Normal University, Beijing 100875, China
ZHU Xiufang	State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China Institute of Remote Sensing Science and Engineering, Faculty of Geographical Science,Beijing Normal University, Beijing 100875, China
PAN Yaozhong	State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing and Digital Earth of Chinese Academy of Sciences, Beijing 100875, China Institute of Remote Sensing Science and Engineering, Faculty of Geographical Science,Beijing Normal University, Beijing 100875, China
ZHANG Jinshui	State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China Institute of Remote Sensing Science and Engineering, Faculty of Geographical Science,Beijing Normal University, Beijing 100875, China

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Abstract:

Radiation parameters are essential for calculating reference crop evapotranspiration (ET₀) by using Penman-Monteith (PM) formula recommended by FAO.To explore the applicability of using the FAO recommended formula for radiation parameter (R_{s_c}) instead of observations (R_{s_o}) in PM formula under the condition of lacking radiation parameters, this study used multi-year monthly average observation data of 112 stations, that each station has at least 15 years of data. The spatiotemporal difference between R_{s_c} and R_{s_o}, and ET₀_c and ET₀_o which obtained by PM formula input of R_{s_c} and R_{s_o}, respectively, by point-by-point was analyzed.The results showed that R_{s_c} and R_{s_o} had significant spatial-temporal differences, and the relative difference between them ranged from -2.86 to 4.41 MJ·m^-2·d^-1, which were larger from April to August. Taking Hu Huanyong Line as the boundary,the spatial-temporal difference in the northwest region of the line was relatively small and stable, while the spatial-temporal difference in the southeast region of the line was relatively large and unstable.However, the spatial-temporal difference of the ET₀_c and ET₀_o calculated by R_{s_c} and R_{s_o}, respectively,was not significant, only 0.06~0.26 mm·d^-1.The absolute difference value between ET₀_c and ET₀_o was stable in 0~0.25 mm·d^-1in northwest of Hu Huanyong Line. The difference in southeast region of the line changed with the season, and the difference in summer was relatively large. In actual application, using R_{s_c} instead of R_{s_o} to obtain ET₀ had a good applicability in the northwest region within a year and also the north region in spring, autumn, winter and the Yangtze river-Pearl river basin (the southern region) in months, Jan., Feb., Oct., Nov. and Dec.If R_{s_c} was used to calculate ET₀ in summer of the north region and from March to September of the south region, corresponding methods must be studied to correct the results.Otherwise, there will be relatively large errors.