中文摘要：

根据一种简化的Penman模型，建立了一个无需风速的参考作物蒸散发模型（Penman—Valiantzas模型），在此基础上又结合Hargreaves辐射方程建立了无需风速和日照时数的Penman—Valiantzas—Hargreaves模型。利用世界粮食组织的CLIMWAT数据库中156个气象站点多年月平均资料对此模型在中国的适用性进行了分析。通过与FAOPen—man-Menteith标准参考作物蒸散发量比较发现，这两个模型的相关性分别为96．64％和93．44％，均方根误差分别为0．32mm／d和0．43mm／d，比目前广泛使用的Priestley—Taylor模型、Hargreaves模型都具有更高的模拟精度。此外，利用北京延庆站的长期气象观测资料对Penman—Valiantzas模型进一步验证，模拟结果与FAOPenman—Menteith估算值和蒸发皿观测值的相关性分别为97．84％、86．38％；在北京站的应用表明，Penman．Valiantzas—Hargreaves模型在日尺度模拟方面也具有较高精度。研究认为，Valiantzas方法适宜在中国使用，是风速、日照时数数据缺乏情况下参考作物蒸散发模拟的较好方法。

英文摘要：

A Penman-Valiantzas model is developed based on the Valiantzas approach for estimating reference evapotranspiration in China without wind speed data. Besides, the Hargreaves radiation equation is used for deriving a Penman-Valiantzas-Hargreaves model, in which only the relative humidity and the air temperature are required as the model input. The two new models are tested with the CLIMWAT database of UN Food and Agricuhure Organization （FAO）. A total of 156 Chinese stations are extracted from the database, which contain long-term monthly mean values of climatic parameters. The result shows that the correlation coefficients between reference evapotranspirations calculated by the two models and the FAO Penman-Menteith model are 96.64% and 93.44% , respectively. The corresponding values of the root mean square error are 0.32 mm/d and 0.43 mm/d, respectively. These two new models can produce a more accurate reference evapotranspiration than that obtained by other two widely used models （Priestley-Taylor and Hargreaves）. The Penman-Valiantzas model is further tested using the long-term measurement observed at the Yanqing Station in Beijing. The result of a 20-year monthly simulation reveals that the correlation coefficients between reference evapotranspirations calculated by the Penman-Valiantzas model and the FAO Penman-Menteith model as well as observed by the pan observation at the station are 97.84% and 86.38% , respectively. The daily simulation of reference evapotranspiration using the Penman-Valiantzas-Hargreaves model has also been improved. Our results demonstrate the applicability of the two new models in China in the absence of the wind speed and sunshine hour data date.