Detailed knowledge of energy and mass fluxes between land and the atmosphere are necessary to monitor the climate of the land and effectively exploit it in growing agricultural commodities. One of the important surface land fluxes is evapotranspiration, which combines the process of evaporation from the soil and that of transpiration from plants, describing the movement of water vapour from the land to the atmosphere. Accurately estimating evapotranspiration in agricultural systems is of high importance for efficient use of water resources and precise irrigation scheduling operations that will lead to improved water use efficiency. This paper reviews the major mechanistic and empirical models for estimating evapotranspiration including the Penman–Monteith, Stanghellini, Priestly–Taylor, and Hargreaves and Samani models. Moreover, the major differences between the models and their underlined assumptions are discussed. The application of these models is also reviewed for both open and closed field mediums and limitations of each model are highlighted. The main parameters affecting evapotranspiration rates in greenhouse settings including aerodynamic resistance, stomatal resistance and intercepted radiation are thoroughly discussed for accurate measurement and consideration in evapotranspiration models. Moreover, this review discusses direct evapotranspiration measurements systems such as eddy covariance and gas exchange systems. Other direct measurements appertaining to specific parameters such as leaf area index and surface leaf temperature and indirect measurements such as remote sensing are also presented, which can be integrated into evapotranspiration models for adaptation depending on climate and physiological characteristics of the growing medium. This review offers important directions for the estimation of evapotranspiration rates depending on the agricultural setting and the available climatological and physiological data, in addition to experimentally based adaptation processes for ET models. It also discusses how accurate evapotranspiration measurements can optimise the energy, water and food nexus.

中文翻译：

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开放和封闭农业田间应用的蒸散测量模型、技术和方法综述

土地和大气之间的能量和质量通量的详细知识对于监测土地的气候和有效地利用它来种植农产品是必要的。重要的地表陆地通量之一是蒸散，它结合了土壤蒸发和植物蒸腾的过程，描述了水蒸气从陆地到大气的运动。准确估计农业系统中的蒸散量对于有效利用水资源和精确的灌溉调度操作非常重要，这将提高用水效率。本文回顾了估计蒸散量的主要机制和经验模型，包括 Penman-Monteith、Stanghellini、Priestly-Taylor 以及 Hargreaves 和 Samani 模型。而且，讨论了模型及其带下划线的假设之间的主要差异。还审查了这些模型在开放和封闭场介质中的应用，并强调了每个模型的局限性。详细讨论了影响温室环境中蒸散速率的主要参数，包括空气动力阻力、气孔阻力和截获辐射，以便在蒸散模型中进行准确测量和考虑。此外，这篇综述讨论了直接蒸散测量系统，如涡流协方差和气体交换系统。还介绍了与特定参数（例如叶面积指数和表面叶温）相关的其他直接测量以及遥感等间接测量，根据气候和生长介质的生理特征，可以将其整合到蒸发蒸腾模型中以进行适应。除了基于实验的 ET 模型适应过程之外，本综述还为根据农业环境和可用的气候和生理数据估算蒸散率提供了重要方向。它还讨论了准确的蒸散测量如何优化能量、水和食物的关系。