Our understanding of water and carbon cycles and their coupling has advanced significantly over the last six decades. In this review, we will examine the progress made since the 1960s and explore how key developments in the studies of water and carbon cycles on land have influenced the way we model these two cycles from leaf to global scales. We will particularly focus on the Penman-Monteith equation for calculating evapotranspiration, the biochemical model of leaf photosynthesis, and the model of stomatal conductance.These three models developed over three decades ago have been widely adopted in the studies of water and carbon cycle from leaf to global scales. The success of these models lie in their sound representation of the basic biophysical and biochemical processes with relative simplicity. Their wide adoption was also assisted by the rapid development of portable leaf gas exchange instruments and field deployment of eddy covariance techniques, which provide the data for estimating the key model parameters and for model evaluation and improvement.Over the last two decades, rapid advances in remote sensing, global eddy flux networks, and computation have led to a rapid growth of different approaches for estimating water and carbon fluxes. This review compares the simulated global gross primary production, evapotranspiration and ecosystem water use efficiency and their trends using these different approaches, and finds that significant progress has been made in understanding their spatial patterns, interannual variations and trends. However, significant divergences remain among them.Looking ahead, we identify several key areas where significant progress is likely, particularly through the applications of machine learning and ecological forecasting. We also anticipate the development of new theories by integrating theoretical understanding with increasing observations from ground and space.

中文翻译：

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从叶片到全球的水和碳循环耦合模型：回顾与展望


在过去的六十年里，我们对水和碳循环及其耦合的理解有了显著的进步。在这篇综述中，我们将研究自 1960 年代以来取得的进展，并探讨陆地水和碳循环研究的关键发展如何影响我们从叶子到全球尺度对这两个循环进行建模的方式。我们将特别关注用于计算蒸散的 Penman-Monteith 方程、叶片光合作用的生化模型和气孔导度模型。这三个模型在三十多年前开发，已被广泛用于从叶片到全球尺度的水和碳循环研究。这些模型的成功在于它们以相对简单的方式正确地表示了基本的生物物理和生化过程。便携式叶片气体交换仪器的快速发展和涡度相关技术的现场部署也有助于它们的广泛采用，这些技术为估计关键模型参数以及模型评估和改进提供了数据。在过去的二十年里，遥感、全球涡流网络和计算的快速发展导致了估计水和碳通量的不同方法的快速增长。本文使用这些不同的方法比较了模拟的全球总初级生产、蒸散和生态系统水分利用效率及其趋势，发现在理解它们的空间模式、年际变化和趋势方面取得了重大进展。然而，他们之间仍然存在重大分歧。展望未来，我们确定了几个可能取得重大进展的关键领域，特别是通过机器学习和生态预测的应用。 我们还通过将理论理解与地面和太空的观测相结合，预计新理论的发展。