Chinese Journal of Agrometeorology ›› 2014, Vol. 35 ›› Issue (04): 380-388.doi: 10.3969/j.issn.1000-6362.2014.04.004

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Simulation Study on Evapotranspiration of Rice Paddy in the Sanjiang Plain

JIA Zhi jun,JI Xing jie   

  1. College of Atmospheric Science,Chengdu University of Information Technology/Plateau Atmosphere and Environment Key Laboratory of Sichuan Province,Chengdu610225,China; Henan Provincial Climate Centre,Zhengzhou450003
  • Received:2013-07-30 Online:2014-08-20 Published:2015-02-11

Abstract: Based on the eddy covariance and microclimate observed data from 2005 to 2007,the simulating accuracy of evapotranspiration(ET)with the Penman,PenmanMonteith(PM)and PriestleyTaylor(PT)models of rice paddy from May to October in the Sanjiang plain was analyzed The results showed that the simulated value of ET by using the Penman model with conventional patters was significantly higher than that of measured ones,with average 103.5%. However the value of ET by using PM and PT model was accurate,with mean bias error (MBE)0.26mm·d-1and 0.02mm·d-1,and root mean square error(RMSE)0.68mm·d-1and 0.71mm·d-1,respectively. There was significant  positive correlation between crop coefficients(Kc)of rice paddy and leaf area index(LAI)by using the Penman  and PM models,and there was positive correlation between α value and LAI,vapor pressure deficit(VPD)and wind speed(WS),even extreme significance with VPD and WS under the PT model. The accuracy of the Penman model was improved obviously after modified by linear regression equation,with MBE 0.28mm·d-1and RMSE 0.64mm·d-1, respectively,and modeling efficiency(ME)changed to 0.75 from a negative value. But the accuracy of PM and PT model was not improved. The simulated value was not significant difference among three models by using variance analysis,which indicated  that the simulating accuracy of three models to evapotranspiration in Sanjiang plain was similar. In conclusion,both of PM and PT model was suitable for estimating the ET of rice paddy in the Sanjiang plain whether the Kc and α were modified or not,while the Penman model was suitable only when the Kc was modified.

Key words: Evapotranspiration model, Crop coefficient, &alpha, value, Rice paddy, Sanjiang plain