Evaluation of Methods of Estimation of Evapotranspiration of Reference (ETo) Daily for Regions of the States of Rio De Janeiro and Espírito Santo

Abstract The high consumption of water by agriculture makes knowledge about reference evapotranspiration (ETo) for irrigation management more and more essential. However, define an appropriate method to the different locations is associated with the availability of meteorological data and the adaptation of the methods to the application sites. Thus, the objective of this study is to compare and evaluate the performance of the ETo methods: Hargreaves-Samani, Jensen-Haise, Benavides & Lopez and Hamon using the standard method Penman Monteith FAO-56, to estimate the daily ETo of six regions, three of the state of Rio de Janeiro and three of the state of Espírito Santo. The meteorological variables employed were provided by the Center for Weather Forecasting and Climate Studies and the National Institute of Space Research - (CPTEC - INPE). The performance of the models was evaluated by different statistical techniques where the model that best suited the studied locations in the two states was the Jensen Haise, obtaining correlation indexes (r) between 0.73 and 0.94 and reliability (C) between 0.60 and 0.90 with the Penman Monteith model.

摘要 农业用水消耗量居高不下，使得参考作物蒸散量（reference evapotranspiration，ETo）相关知识在灌溉管理中的应用价值愈发凸显。然而，为不同地域遴选适配的ETo估算方法，往往受限于气象数据的可获取性，以及方法对应用场景的适配性。为此，本研究以FAO-56彭曼-蒙特斯（Penman Monteith FAO-56）标准方法为参照基准，对比评估Hargreaves-Samani、Jensen-Haise、Benavides & Lopez以及Hamon四种ETo估算方法的性能，以估算里约热内卢州3个区域与圣埃斯皮里图州3个区域共计6个区域的逐日参考作物蒸散量。本研究所用气象数据由巴西国家空间研究院气候预报与气候研究中心（CPTEC - INPE）提供。研究借助多种统计技术对各模型的性能开展评估，结果表明：Jensen-Haise模型最适配两个州的研究区域，其与彭曼-蒙特斯模型的相关系数（r）取值区间为0.73至0.94，可信度（C）取值区间为0.60至0.90。