Improvement of evapotranspiration models in summer maize field and its sensitivities analysis to the resistance parameters
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DOI:10.7606/j.issn.1000-7601.2018.02.09
Key Words: shuttleworth-wallace model  evapotranspiration  canopy resistance  effective leaf area index  soil resistance  maize field
Author NameAffiliation
PENG Ji-yong Key Laboratory of Agrometeorological Services and Applied Technique, China Meteorological Administration, Zhengzhou, Henan 450003, China
Henan Institute of Meteorological Science, Zhengzhou, Henan 450003, China 
YANG Guang-xian Key Laboratory of Agrometeorological Services and Applied Technique, China Meteorological Administration, Zhengzhou, Henan 450003, China
Henan Institute of Meteorological Science, Zhengzhou, Henan 450003, China 
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Abstract:
      Four Shuttleworth-Wallace (S-W) models were used to simulate hourly evapotranspiration (ET) in the grain filling stage of summer maize by different canopy resistance models and soil surface resistance model. In order to determine the optimum model of canopy resistance and soil surface resistance, the effect of the improved model was measured by eddy correlation method of evapotranspiration. The sensitivity of the optimal resistance parameters was also analyzed. The results showed thatthe improved S-W model had the best simulation results. After S-W model was improved, the accuracy of estimation of maize field evapotranspiration was significantly improved. The correlation coefficient and the consistency index of ET simulated and measured values were close to 1, and the relative error and root mean square error of ET simulation became smaller. Sensitivity analysis showed that the canopy resistance was the most sensitive parameter, the second was the soil surface resistance, and the third was the effective leaf area index. To a certain degree, the model precision was improved by using the improved effective leaf area index canopy resistance model and the soil surface resistance model, which can improve the accuracy of the model calculation.