辐射参数计算方法对参考作物蒸发蒸腾量计算值的影响

采用FAO-56PM公式和其他计算公式计算净辐射Rn和参考作物蒸发蒸腾量ET0,对不同方法所得Rn计算值进行了比较.结果表明,不同辐射参数计算值对Rn计算值影响不同,大气边缘辐射计算值对Rn影响很大,Irmak方法和Allen方法所得Rn与FAO-56PM公式结果较一致.进一步以不同方法所得Rn代入FAO-56PM公式计算ET0,Irmak方法和Allen方法所得ET0与FAO-56PM公式计算值较一致.敏感性分析表明,Rn波动10%,ET0波动在7%左右,Rn对ET0的影响很大.在中亚热带低丘岗地区估算ET0时,可考虑Irmak方法和Allen方法来估算Rn.

Influence of calculation methods for radiation parameters on the calculated reference crop evapotranspiration

Net radiation,Rn,and reference crop evapotranspiration,ET0,were calculated using FAO-56PM equation and other formulas,and the results from each method were compared.The results show that different radiation parameters have different influences on Rn,and the calculated extraterrestrial radiation has a very significant influence on Rn.The Rn values calculated from the Irmak Method and the Allen Method and the corresponding ET0 are almost identical to the results from FAO-56PM equation.This indicates that the Irmak Method and the Allen Method can be used to calculate ET0 in hillock areas in the middle subtropical zone.Sensitivity analyses show that one unit variation in Rn will produce 0.7 unit variation in ET0.