Jerszurki Daniela, Souza Jorge L M, Silva Lucas C R
Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer, Israel.
Soil and Environment Studies Program, Federal University of Paraná, Curitiba, Paraná, Brazil.
PLoS One. 2017 Jun 28;12(6):e0180055. doi: 10.1371/journal.pone.0180055. eCollection 2017.
The development of new reference evapotranspiration (ETo) methods hold significant promise for improving our quantitative understanding of climatic impacts on water loss from the land to the atmosphere. To address the challenge of estimating ETo in tropical and subtropical regions where direct measurements are scarce we tested a new method based on geographical patterns of extraterrestrial radiation (Ra) and atmospheric water potential (Ψair). Our approach consisted of generating daily estimates of ETo across several climate zones in Brazil-as a model system-which we compared with standard EToPM (Penman-Monteith) estimates. In contrast with EToPM, the simplified method (EToMJS) relies solely on Ψair calculated from widely available air temperature (oC) and relative humidity (%) data, which combined with Ra data resulted in reliable estimates of equivalent evaporation (Ee) and ETo. We used regression analyses of Ψair vs EToPM and Ee vs EToPM to calibrate the EToMJS(Ψair) and EToMJS estimates from 2004 to 2014 and between seasons and climatic zone. Finally, we evaluated the performance of the new method based on the coefficient of determination (R2) and correlation (R), index of agreement "d", mean absolute error (MAE) and mean reason (MR). This evaluation confirmed the suitability of the EToMJS method for application in tropical and subtropical regions, where the climatic information needed for the standard EToPM calculation is absent.
新的参考蒸散量（ETo）方法的发展对于提高我们对气候对陆地向大气水分流失影响的定量理解具有重大前景。为应对热带和亚热带地区直接测量稀缺情况下估算ETo的挑战，我们测试了一种基于地外辐射（Ra）和大气水势（Ψair）地理模式的新方法。我们的方法包括在巴西的几个气候区生成ETo的每日估算值——作为一个模型系统——并将其与标准的EToPM（彭曼 - 蒙特斯）估算值进行比较。与EToPM不同，简化方法（EToMJS）仅依赖于根据广泛可得的气温（℃）和相对湿度（%）数据计算得出的Ψair，该数据与Ra数据相结合得出了等效蒸发量（Ee）和ETo的可靠估算值。我们使用Ψair与EToPM以及Ee与EToPM的回归分析来校准2004年至2014年期间以及不同季节和气候区的EToMJS（Ψair）和EToMJS估算值。最后，我们基于决定系数（R2）、相关性（R）、一致性指数“d”、平均绝对误差（MAE）和平均偏差（MR）评估了新方法的性能。该评估证实了EToMJS方法适用于热带和亚热带地区，在这些地区缺乏标准EToPM计算所需的气候信息。
