几种蒸散计算方法在怀来地区的适用性研究

Applicability of Evapotranspiration Estimation Methods in the Huailai Region of Hebei Province

作物蒸散量即为植株蒸腾与棵间蒸发之和,准确地测定作物实际蒸散量,对研究农作物节水种植技术、加强水资源管理和制定合理的灌溉计划具有十分重要的意义。文章应用2013年生长季(5-10月)自动称重式蒸渗仪实测河北怀来地区夏玉米的蒸散量,从月、日两个时间尺度评价Penman-Monteith(FAO P-M)、Hargreaves、Priestley-Taylor三种基于参考作物蒸散量计算实际蒸散的方法在怀来地区的适用性,结果表明:(1)三种方法计算的夏玉米月、日实际蒸散相对于蒸渗仪实测结果均存在一定偏差,FAO P-M方法与Hargreaves方法表现较好,准确度相差不大,Priestley-Taylor方法准确性最差;(2)影响实际蒸散计算结果的主要气象因子为太阳净辐射和温度,Hargreaves方法计算结果在怀来地区可信度较高;(3)Hargreaves方法所需参数较少,在计算量方面占有很大的优势,在怀来地区适用性最好。

The evapotranspiration of the cropland is the sum of plant transpiration and soil evaporation. Assessment of actual evapotranspiration of crops is very important for the water saving technology, water resource management and reasonable irrigation plan. In this paper, the actual evapotranspiration of summer corn measured by automatic weighing lysimeter during the growing season （April to September） in 2013 is used to evaluate the applicability of Penman Monteith （FAO P M）, Hargreaves, and Priestley Taylor methods in the Huailai Region of Hebei Province. Correlation coefficients, the root mean square error （RMSE）, consistency index （d） and other indicators are applied, in monthly and daily time scales, to compare the accuracy of the three methods. The results show that： （1） compared with lysimeter measured results, summer maize monthly actual evapotranspiration calculated by the three methods have some deviations; FAO P M method and Hargreaves method show good performance and accuracy; the accuracy of P T method is the worst. （2） The main meteorological factors that affect the actual evapotranspiration calculation results are the net radiation of the sun and temperature. （3） The Hargreaves method needs fewer parameters and has a great advantage in computing, and it is credible in assessing actual evapotranspiration in Huailai.