华北地区玉米田实际蒸散量的计算

ESTIMATION OF ACTUAL EVAPOTRANSPIRATION FOR MAIZE FIELD IN NORTH CHINA

以简化农田实际蒸散的计算过程为目的 ,利用 1 999年河北定兴县中国气象科学研究院农业气象试验基地的玉米田 0～ 30 0cm土壤湿度和气象要素的实测资料以及华北地区 5个站 1 991～ 1 995年 0～ 5 0cm土壤湿度和气象资料 ,探讨由简化参考蒸散模式计算玉米田实际蒸散的可能性 ;对比了Priestley Taylor模式和FAO( 1 998)Penman Menteith模式的计算结果 ,以农田试验资料为基础 ,采用叶面积系数和平均土壤相对湿度为因子 ,建立了实际蒸散的计算模式。并以华北地区 8个站 1 999～ 2 0 0 0年 0～ 5 0cm土壤湿度和气象资料进行验证 ,平均误差一般为 1 0 %～ 1 5 %。

For simplifying the calculation of actual evapotranspiration in cropped field,the soil moisture of the depth from 0 to 300 cm in the maize field and the meteorological observational data in 1999 at Dingxin county in Hebei province,where is an agrometeorological experiment base of Chinese Academy of Meteorological Sciences,and the soil moisture of the depth from 0 to 50 cm and the meteorological observational data at 5 stations in North China from 1991 to 1995 are used. The possibility that actual evapotranspiration in the maize field is calculated by using a simple reference evapotranspiration model is examined. Priestley-Taylor modeland FAO Penman-Menteith (1998) model are compared and the factors impacting on evapotranspiration are discussed. Based on the experimental data and using leaf area coefficient and mean soil relative moisture as the model factors, A formula calculating actual evapotranspiration is made. Evapotranspiration is calculated by this formula, and the soil moisture of the depth from 0 to 50 cm and the meteorological observational data at 8 stations from 1999 to 2000 are applied to validate. The average errors are in the range from 10% to 15% generally.