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| DOI： |
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| Sensitivity Analysis of the Reference Crop Evapotranspiration to Meteorological Factors |
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LI Ying, LYU Mouchao, ZHANG Haiwen, DENG Zhong, LIU Chuncheng, JIANG Mingliang
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Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang 453002, China; Beijing Vocational College of Agriculture, Beijing 102442, China
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| Abstract: |
| Calculating the reference crop evapotranspiration (ET0) from the Penman-Monteith formula needs a number of meteorological data and we analyzed the sensitivity of the ET0 to different meteorological factors using weather data measured daily in Xinxiang from 1951 to 2003. We firstly calculated the ET0 using these measured data and the Penman-Monteith formula, and then analyzed its sensitivities to different meteorological factors based on the sensitivity curves and sensitivity coefficients. The results showed that the ET0 was correlated positively with temperature (T), wind speed (U2) and sunshine hours (n), and negatively with the relative humidity (RH). From January to December, the sensitive coefficients of ET0 to RH and WS decreased first and then increased, but its sensitive coefficients to SH and T increased first and then decreased. The sensitivity of annual ET0 to meteorological factors was in the order of RH>U2>n>T. Seasonally, the sensitivity of ET0 to meteorological factors was in the order of RH>U2>n>T in the first and fourth quarters, RH>n>U2>T in the second quarter, and RH>n>T>U2 in the third quarter. In critical growing season, the sensitivity of ET0 to meteorological factors was in RH>U2>n>T in January, March and October, and RH>n>U2>T in May. |
| Key words: reference crop evapotranspiration; meteorological factors; sensitivity; sensitivity curve; sensitive coefficient |
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