中文摘要：

利用Penman-Monteith公式估算参考作物蒸散,研究了日尺度参考作物蒸散（ET0d）和日内小时尺度参考作物蒸散之和（ET0dh）的关系。结果表明,ET0d和ET0dh以及实际日尺度和日内小时尺度作物系数均显著线性相关;基于Penman-Monteith公式的日尺度和小时尺度参考作物蒸散估算方法可用于作物系数的作物蒸散时间尺度转换。

英文摘要：

Using the method of estimating reference evapotranspiration by Penman-Monteith formula, the relationship between the daily reference evapotranspiration（ETod） and the sum of 24 hourly reference evap- otranspirations within a day （ET0ah） was researched. The results showed that there existed significant line- ar relationships between ETod and ETodh as well as kcd and kch. The method of estimating reference evapo- transpiration by Penman-Monteith formula could be used for the change of evapotranspiration time scales for crop coefficient.